diff --git a/backend/contest/services.py b/backend/contest/services.py
index b9c06d7..8a3cc39 100644
--- a/backend/contest/services.py
+++ b/backend/contest/services.py
@@ -435,6 +435,11 @@ def match_payload(match, user):
                     if reveal_results and opponent_attempt
                     else None
                 ),
+                "duration_ms": (
+                    opponent_attempt.duration_ms
+                    if reveal_results and opponent_attempt
+                    else None
+                ),
             }
             if opponent
             else None
@@ -481,12 +486,13 @@ def refresh_match_state(match_id):
     elif match.status == RealtimeMatch.Status.ACTIVE and match.started_at:
         deadline = match.started_at + timedelta(seconds=match.contest.duration_seconds)
         if timezone.now() >= deadline:
-            elapsed_ms = match.contest.duration_seconds * 1000
-            match.attempts.filter(status=ContestAttempt.Status.ACTIVE).update(
-                status=ContestAttempt.Status.EXPIRED,
-                duration_ms=elapsed_ms,
-                submitted_at=timezone.now(),
-            )
+            now = timezone.now()
+            for attempt in match.attempts.filter(status=ContestAttempt.Status.ACTIVE):
+                elapsed_ms = max(0, int((now - attempt.started_at).total_seconds() * 1000))
+                attempt.status = ContestAttempt.Status.EXPIRED
+                attempt.duration_ms = elapsed_ms
+                attempt.submitted_at = now
+                attempt.save(update_fields=["status", "duration_ms", "submitted_at"])
             match = finalize_match(match.id)
     return match
 
@@ -516,7 +522,15 @@ def finalize_match(match_id):
         first_result, second_result = 0.0, 1.0
         match.winner_id = second.user_id
     else:
-        first_result = second_result = 0.5
+        diff = first.duration_ms - second.duration_ms
+        if abs(diff) <= 100:
+            first_result = second_result = 0.5
+        elif diff < 0:
+            first_result, second_result = 1.0, 0.0
+            match.winner_id = first.user_id
+        else:
+            first_result, second_result = 0.0, 1.0
+            match.winner_id = second.user_id
 
     users = {
         user.id: user
diff --git a/backend/contest/test_tiebreak.py b/backend/contest/test_tiebreak.py
new file mode 100644
index 0000000..e370a46
--- /dev/null
+++ b/backend/contest/test_tiebreak.py
@@ -0,0 +1,318 @@
+"""端到端模拟两人实时竞赛，覆盖同分不同时长的平局判定场景。"""
+
+import pytest
+from django.test import Client
+from django.utils import timezone
+from datetime import timedelta
+
+from accounts.models import User
+from contest.models import (
+    Contest,
+    ContestAttempt,
+    ContestQuestion,
+    Question,
+    QuestionVersion,
+    RealtimeMatch,
+)
+
+
+def _setup_realtime_contest(db, slug="tiebreak-contest", duration=60):
+    question = Question.objects.create(
+        slug=f"{slug}-q",
+        track=Question.Track.STANDARD,
+    )
+    version = QuestionVersion.objects.create(
+        question=question,
+        version=1,
+        prompt="18 + 24",
+        answer="42",
+        explanation="18 + 24 = 42",
+    )
+    contest = Contest.objects.create(
+        slug=slug,
+        title="同分决胜测试赛",
+        kind=Contest.Kind.REALTIME,
+        track=Question.Track.STANDARD,
+        status=Contest.Status.PUBLISHED,
+        duration_seconds=duration,
+    )
+    ContestQuestion.objects.create(
+        contest=contest,
+        question_version=version,
+        order=1,
+        points=100,
+    )
+    return contest
+
+
+def _create_user(username, nickname):
+    return User.objects.create_user(
+        username=username,
+        password="StrongPass_2026",
+        nickname=nickname,
+    )
+
+
+def _client(user):
+    c = Client()
+    c.force_login(user)
+    return c
+
+
+def _create_and_join(first_client, second_client, contest):
+    created = first_client.post(
+        f"/api/v1/contests/{contest.slug}/challenges/",
+        {},
+        content_type="application/json",
+    )
+    assert created.status_code == 201
+    code = created.json()["challenge_code"]
+
+    joined = second_client.post(
+        "/api/v1/contests/challenges/join/",
+        {"challenge_code": code},
+        content_type="application/json",
+    )
+    assert joined.status_code == 200
+    assert joined.json()["status"] == "active"
+    match_id = joined.json()["match_id"]
+
+    first_state = first_client.get(f"/api/v1/contests/matches/{match_id}/").json()
+    second_state = second_client.get(f"/api/v1/contests/matches/{match_id}/").json()
+    return match_id, first_state, second_state
+
+
+def _set_start(match, user, seconds_ago):
+    """统一设置 match 和 attempt 的 started_at。"""
+    t = timezone.now() - timedelta(seconds=seconds_ago)
+    match.started_at = t
+    match.save(update_fields=["started_at"])
+    match.attempts.filter(user=user).update(started_at=t)
+
+
+def _submit(client, attempt_id, answer, key):
+    return client.post(
+        f"/api/v1/contests/attempts/{attempt_id}/submit/",
+        {"answers": [{"order": 1, "answer": answer}]},
+        content_type="application/json",
+        HTTP_IDEMPOTENCY_KEY=key,
+    )
+
+
+@pytest.mark.django_db
+def test_同分但一方更快则快者胜(db):
+    """两人答对同一题，但提交时间不同，用时短者获胜。"""
+    contest = _setup_realtime_contest(db, "tiebreak-fast")
+    first = _create_user("tie_p1", "快方")
+    second = _create_user("tie_p2", "慢方")
+    fc, sc = _client(first), _client(second)
+
+    match_id, fs, ss = _create_and_join(fc, sc, contest)
+    fa, sa = fs["attempt"]["attempt_id"], ss["attempt"]["attempt_id"]
+
+    match = RealtimeMatch.objects.get(id=match_id)
+    _set_start(match, first, 5)
+    r1 = _submit(fc, fa, "42", "tie-fast-one")
+    assert r1.status_code == 200
+
+    _set_start(match, second, 15)
+    r2 = _submit(sc, sa, "42", "tie-fast-two")
+    assert r2.status_code == 200
+
+    final = fc.get(f"/api/v1/contests/matches/{match_id}/").json()
+    assert final["status"] == "completed"
+    assert final["result"]["winner"] == "self"
+    assert final["attempt"]["score"] == 100
+    assert final["opponent"]["score"] == 100
+    assert final["attempt"]["duration_ms"] < final["opponent"]["duration_ms"]
+
+
+@pytest.mark.django_db
+def test_同分且同时长则平局(db):
+    """两人答对同一题且用时完全相同，判平局。"""
+    contest = _setup_realtime_contest(db, "tiebreak-draw")
+    first = _create_user("draw_p1", "甲")
+    second = _create_user("draw_p2", "乙")
+    fc, sc = _client(first), _client(second)
+
+    match_id, fs, ss = _create_and_join(fc, sc, contest)
+    fa, sa = fs["attempt"]["attempt_id"], ss["attempt"]["attempt_id"]
+
+    match = RealtimeMatch.objects.get(id=match_id)
+    _set_start(match, first, 5)
+    _submit(fc, fa, "42", "draw-one")
+
+    _set_start(match, second, 5)
+    _submit(sc, sa, "42", "draw-two")
+
+    final = fc.get(f"/api/v1/contests/matches/{match_id}/").json()
+    assert final["status"] == "completed"
+    assert final["result"]["winner"] == "draw"
+
+
+@pytest.mark.django_db
+def test_一方答对一方答错则答对者胜(db):
+    """一人答对一人答错，答对者胜（不受时间影响）。"""
+    contest = _setup_realtime_contest(db, "tiebreak-correct")
+    first = _create_user("corr_p1", "答对方")
+    second = _create_user("corr_p2", "答错方")
+    fc, sc = _client(first), _client(second)
+
+    match_id, fs, ss = _create_and_join(fc, sc, contest)
+    fa, sa = fs["attempt"]["attempt_id"], ss["attempt"]["attempt_id"]
+
+    match = RealtimeMatch.objects.get(id=match_id)
+    _set_start(match, first, 3)
+    _submit(fc, fa, "42", "corr-one")
+
+    _set_start(match, second, 10)
+    _submit(sc, sa, "0", "corr-two")
+
+    final = fc.get(f"/api/v1/contests/matches/{match_id}/").json()
+    assert final["status"] == "completed"
+    assert final["result"]["winner"] == "self"
+    assert final["attempt"]["score"] == 100
+    assert final["opponent"]["score"] == 0
+
+
+@pytest.mark.django_db
+def test_双方都答错则快者胜(db):
+    """两人都答错，分数相同（0 分），比较用时，快者胜。"""
+    contest = _setup_realtime_contest(db, "tiebreak-both-wrong")
+    first = _create_user("wrong_p1", "快错")
+    second = _create_user("wrong_p2", "慢错")
+    fc, sc = _client(first), _client(second)
+
+    match_id, fs, ss = _create_and_join(fc, sc, contest)
+    fa, sa = fs["attempt"]["attempt_id"], ss["attempt"]["attempt_id"]
+
+    match = RealtimeMatch.objects.get(id=match_id)
+    _set_start(match, first, 5)
+    _submit(fc, fa, "0", "wrong-one")
+
+    _set_start(match, second, 12)
+    _submit(sc, sa, "0", "wrong-two")
+
+    final = fc.get(f"/api/v1/contests/matches/{match_id}/").json()
+    assert final["status"] == "completed"
+    assert final["result"]["winner"] == "self"
+    assert final["attempt"]["score"] == 0
+    assert final["opponent"]["score"] == 0
+
+
+@pytest.mark.django_db
+def test_超时提交导致分数为零_同分时比较用时(db):
+    """一方超时提交（分数为 0），另一方正常提交也得 0 分，同分快者胜。"""
+    contest = _setup_realtime_contest(db, "tiebreak-timeout", duration=10)
+    first = _create_user("to_p1", "超时方")
+    second = _create_user("to_p2", "正常零分方")
+    fc, sc = _client(first), _client(second)
+
+    match_id, fs, ss = _create_and_join(fc, sc, contest)
+    fa, sa = fs["attempt"]["attempt_id"], ss["attempt"]["attempt_id"]
+
+    match = RealtimeMatch.objects.get(id=match_id)
+    _set_start(match, first, 20)
+    r1 = _submit(fc, fa, "42", "to-one")
+    assert r1.status_code == 200
+    assert r1.json()["attempt"]["status"] == "expired"
+
+    _set_start(match, second, 3)
+    _submit(sc, sa, "0", "to-two")
+
+    final = fc.get(f"/api/v1/contests/matches/{match_id}/").json()
+    assert final["status"] == "completed"
+    assert final["attempt"]["score"] == 0
+    assert final["opponent"]["score"] == 0
+    assert final["result"]["winner"] == "opponent"
+
+
+@pytest.mark.django_db
+def test_随机匹配同分快者胜(db):
+    """通过随机匹配（非联机码）也能正确触发同分快者胜。"""
+    contest = _setup_realtime_contest(db, "tiebreak-random")
+    first = _create_user("rnd_p1", "随机快")
+    second = _create_user("rnd_p2", "随机慢")
+    fc, sc = _client(first), _client(second)
+
+    r1 = fc.post(
+        f"/api/v1/contests/{contest.slug}/matchmaking/",
+        {},
+        content_type="application/json",
+    )
+    r2 = sc.post(
+        f"/api/v1/contests/{contest.slug}/matchmaking/",
+        {},
+        content_type="application/json",
+    )
+    assert r1.json()["status"] == "active" or r2.json()["status"] == "active"
+
+    match_id = r1.json().get("match_id") or r2.json()["match_id"]
+    fs = fc.get(f"/api/v1/contests/matches/{match_id}/").json()
+    ss = sc.get(f"/api/v1/contests/matches/{match_id}/").json()
+    fa, sa = fs["attempt"]["attempt_id"], ss["attempt"]["attempt_id"]
+
+    match = RealtimeMatch.objects.get(id=match_id)
+    _set_start(match, first, 4)
+    _submit(fc, fa, "42", "rnd-one")
+
+    _set_start(match, second, 8)
+    _submit(sc, sa, "42", "rnd-two")
+
+    final = fc.get(f"/api/v1/contests/matches/{match_id}/").json()
+    assert final["status"] == "completed"
+    assert final["result"]["winner"] == "self"
+    assert final["attempt"]["score"] == 100
+    assert final["opponent"]["score"] == 100
+
+
+@pytest.mark.django_db
+def test_rating_变化在同分快者胜时正确(db):
+    """同分快者胜时，Elo rating 按正常胜负变化（不平局）。"""
+    contest = _setup_realtime_contest(db, "tiebreak-rating")
+    first = _create_user("rate_p1", "Rating快")
+    second = _create_user("rate_p2", "Rating慢")
+    fc, sc = _client(first), _client(second)
+
+    match_id, fs, ss = _create_and_join(fc, sc, contest)
+    fa, sa = fs["attempt"]["attempt_id"], ss["attempt"]["attempt_id"]
+
+    match = RealtimeMatch.objects.get(id=match_id)
+    _set_start(match, first, 5)
+    _submit(fc, fa, "42", "rate-one")
+
+    _set_start(match, second, 12)
+    _submit(sc, sa, "42", "rate-two")
+
+    first.refresh_from_db()
+    second.refresh_from_db()
+    assert first.rating > 1000
+    assert second.rating < 1000
+
+
+@pytest.mark.django_db
+def test_双方都超时则由_refresh_自动结算判平(db):
+    """双方都超时（分数都为 0），refresh_match_state 自动结算，duration 统一为时限，判平。"""
+    contest = _setup_realtime_contest(db, "tiebreak-both-timeout", duration=10)
+    first = _create_user("both_to_p1", "快超时")
+    second = _create_user("both_to_p2", "慢超时")
+    fc, sc = _client(first), _client(second)
+
+    match_id, fs, ss = _create_and_join(fc, sc, contest)
+    fa, sa = fs["attempt"]["attempt_id"], ss["attempt"]["attempt_id"]
+
+    # 两个人都不提交，直接让 match 超时
+    match = RealtimeMatch.objects.get(id=match_id)
+    match.started_at = timezone.now() - timedelta(seconds=15)
+    match.save(update_fields=["started_at"])
+    match.attempts.update(started_at=match.started_at)
+
+    from contest.services import refresh_match_state
+    refresh_match_state(match.id)
+
+    final = fc.get(f"/api/v1/contests/matches/{match_id}/").json()
+    assert final["status"] == "completed"
+    assert final["attempt"]["score"] == 0
+    assert final["opponent"]["score"] == 0
+    # 双方都超时，duration_ms 相同（都约 15000ms），判平
+    assert final["result"]["winner"] == "draw"
diff --git a/backend/static/css/app.css b/backend/static/css/app.css
index a33aafb..c367579 100644
--- a/backend/static/css/app.css
+++ b/backend/static/css/app.css
@@ -139,6 +139,8 @@ button { color: inherit; }
 .realtime-progress-panel { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-bottom: 18px; }.realtime-progress-panel > div { padding: 13px 15px; border-radius: 12px; background: #eef1eb; }.realtime-progress-panel span, .realtime-progress-panel b { display: block; }.realtime-progress-panel span { color: var(--muted); font-size: 10px; }.realtime-progress-panel b { margin-top: 5px; color: var(--green); }
 .realtime-answer-form input { margin-top: 7px; width: 100%; padding: 12px; border: 1px solid #d6d8d1; border-radius: 9px; }.realtime-submitted { margin-top: 20px; padding: 30px; border-radius: 16px; background: var(--ink); color: white; text-align: center; }.realtime-submitted strong { color: var(--lime); font: 27px Georgia, serif; }.realtime-submitted p { margin-bottom: 0; color: #b9c2bc; }
 .realtime-result { margin: 20px 0; padding: 28px; border-radius: 17px; background: var(--ink); color: white; text-align: center; }.realtime-result > strong { color: var(--lime); font: 38px Georgia, serif; }.realtime-result p { color: #c5cec8; }.realtime-result > b { display: inline-block; padding: 6px 10px; border-radius: 99px; background: rgba(204,232,91,.13); color: var(--lime); }.result-opponent > strong { color: #ef947c; }
+.realtime-time-line { margin: 10px 0 6px; font-size: 13px; color: #9ba89d; }
+.realtime-tiebreak { display: block; margin-top: 6px; font-size: 11px; color: var(--lime); font-weight: 700; }
 .realtime-review { display: grid; gap: 9px; }.realtime-review article { padding: 15px; border: 1px solid var(--line); border-left: 4px solid var(--green); border-radius: 11px; background: white; }.realtime-review article.incorrect { border-left-color: #c05245; }.realtime-review p { margin: 7px 0; color: #3e4942; }.realtime-review small { color: var(--muted); }
 .math-games-section { margin-top: 60px; }
 .game-card-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
diff --git a/backend/static/js/realtime.js b/backend/static/js/realtime.js
index aeee0a4..6ada6ab 100644
--- a/backend/static/js/realtime.js
+++ b/backend/static/js/realtime.js
@@ -329,11 +329,25 @@
     const score = document.createElement("p");
     score.textContent =
       `你 ${match.attempt.score} 分 · ${match.opponent.score} 分 ${match.opponent.nickname}`;
+    const timeLine = document.createElement("p");
+    timeLine.className = "realtime-time-line";
+    const selfMs = match.attempt.duration_ms || 0;
+    const opponentMs = match.opponent.duration_ms || 0;
+    const selfSec = (selfMs / 1000).toFixed(1);
+    const opponentSec = (opponentMs / 1000).toFixed(1);
+    timeLine.textContent = `你 ${selfSec}s · ${match.opponent.nickname} ${opponentSec}s`;
+    if (match.attempt.score === match.opponent.score && match.result.winner !== "draw") {
+      const faster = selfMs < opponentMs ? "你" : match.opponent.nickname;
+      const tiebreak = document.createElement("small");
+      tiebreak.className = "realtime-tiebreak";
+      tiebreak.textContent = `同分，${faster}更快完成，快者胜`;
+      timeLine.append(tiebreak);
+    }
     const rating = document.createElement("b");
     const sign = match.result.rating_delta > 0 ? "+" : "";
     rating.textContent =
       `Rating ${sign}${match.result.rating_delta} → ${match.result.rating_after}`;
-    result.append(outcome, score, rating);
+    result.append(outcome, score, timeLine, rating);
     root.append(result);
 
     const review = document.createElement("div");