diff --git a/web/alliance_selection.go b/web/alliance_selection.go
index 9f817d7..765659f 100755
--- a/web/alliance_selection.go
+++ b/web/alliance_selection.go
@@ -137,8 +137,27 @@ func (web *Web) allianceSelectionResetHandler(w http.ResponseWriter, r *http.Req
 		return
 	}
 
-	if !web.canModifyAllianceSelection() {
-		web.renderAllianceSelection(w, r, "Alliance selection has already been finalized.")
+	if !web.canResetAllianceSelection() {
+		web.renderAllianceSelection(w, r, "Cannot reset alliance selection; playoff matches have already started.")
+		return
+	}
+
+	// Delete any elimination matches that were already created (but not played since they would fail the above check).
+	matches, err := web.arena.Database.GetMatchesByType("elimination")
+	if err != nil {
+		handleWebErr(w, err)
+		return
+	}
+	for _, match := range matches {
+		if err = web.arena.Database.DeleteMatch(match.Id); err != nil {
+			handleWebErr(w, err)
+			return
+		}
+	}
+
+	// Delete the saved alliances.
+	if err = web.arena.Database.TruncateAllianceTeams(); err != nil {
+		handleWebErr(w, err)
 		return
 	}
 
@@ -233,8 +252,9 @@ func (web *Web) allianceSelectionPublishHandler(w http.ResponseWriter, r *http.R
 }
 
 func (web *Web) renderAllianceSelection(w http.ResponseWriter, r *http.Request, errorMessage string) {
-	if len(web.arena.AllianceSelectionAlliances) == 0 && !web.canModifyAllianceSelection() {
-		// The application was restarted since the alliance selection was conducted; reload the alliances from the DB.
+	if len(web.arena.AllianceSelectionAlliances) == 0 {
+		// The application may have been restarted since the alliance selection was conducted; try reloading the
+		// alliances from the DB.
 		var err error
 		web.arena.AllianceSelectionAlliances, err = web.arena.Database.GetAllAlliances()
 		if err != nil {
@@ -273,6 +293,20 @@ func (web *Web) canModifyAllianceSelection() bool {
 	return true
 }
 
+// Returns true if it is safe to reset the alliance selection (i.e. no elimination matches have been played yet).
+func (web *Web) canResetAllianceSelection() bool {
+	matches, err := web.arena.Database.GetMatchesByType("elimination")
+	if err != nil {
+		return false
+	}
+	for _, match := range matches {
+		if match.Status != model.MatchNotPlayed {
+			return false
+		}
+	}
+	return true
+}
+
 // Returns the row and column of the next alliance selection spot that should have keyboard autofocus.
 func (web *Web) determineNextCell() (int, int) {
 	// Check the first two columns.
diff --git a/web/alliance_selection_test.go b/web/alliance_selection_test.go
index 390da07..a4ea0a5 100644
--- a/web/alliance_selection_test.go
+++ b/web/alliance_selection_test.go
@@ -141,9 +141,6 @@ func TestAllianceSelectionErrors(t *testing.T) {
 	recorder = web.postHttpResponse("/alliance_selection/finalize", "startTime=2014-01-01 01:00:00 PM")
 	assert.Equal(t, 200, recorder.Code)
 	assert.Contains(t, recorder.Body.String(), "already been finalized")
-	recorder = web.postHttpResponse("/alliance_selection/reset", "")
-	assert.Equal(t, 200, recorder.Code)
-	assert.Contains(t, recorder.Body.String(), "already been finalized")
 	recorder = web.postHttpResponse("/alliance_selection", "selection0_0=asdf")
 	assert.Equal(t, 200, recorder.Code)
 	assert.Contains(t, recorder.Body.String(), "already been finalized")
@@ -154,6 +151,62 @@ func TestAllianceSelectionErrors(t *testing.T) {
 	assert.Contains(t, recorder.Body.String(), "already been finalized")
 }
 
+func TestAllianceSelectionReset(t *testing.T) {
+	web := setupTestWeb(t)
+
+	web.arena.AllianceSelectionAlliances = [][]model.AllianceTeam{}
+	cachedRankedTeams = []*RankedTeam{}
+	web.arena.EventSettings.NumElimAlliances = 2
+	for i := 1; i <= 6; i++ {
+		web.arena.Database.CreateRanking(&game.Ranking{TeamId: 100 + i, Rank: i})
+	}
+
+	// Start, populate, and finalize the alliance selection.
+	recorder := web.postHttpResponse("/alliance_selection/start", "")
+	assert.Equal(t, 303, recorder.Code)
+	recorder = web.postHttpResponse("/alliance_selection", "selection0_0=101&selection0_1=102&selection0_2=103&"+
+		"selection1_0=104&selection1_1=105&selection1_2=106")
+	assert.Equal(t, 303, recorder.Code)
+	recorder = web.postHttpResponse("/alliance_selection/finalize", "startTime=2014-01-01 01:00:00 PM")
+	assert.Equal(t, 303, recorder.Code)
+	alliances, _ := web.arena.Database.GetAllAlliances()
+	assert.NotEmpty(t, alliances)
+	matches, _ := web.arena.Database.GetMatchesByType("elimination")
+	assert.NotEmpty(t, matches)
+
+	// Reset the alliance selection before any matches have been played.
+	recorder = web.postHttpResponse("/alliance_selection/reset", "")
+	assert.Equal(t, 303, recorder.Code)
+	alliances, _ = web.arena.Database.GetAllAlliances()
+	assert.Empty(t, alliances)
+	matches, _ = web.arena.Database.GetMatchesByType("elimination")
+	assert.Empty(t, matches)
+
+	// Start, populate, and finalize the alliance selection again.
+	recorder = web.postHttpResponse("/alliance_selection/start", "")
+	assert.Equal(t, 303, recorder.Code)
+	recorder = web.postHttpResponse("/alliance_selection", "selection0_0=101&selection0_1=102&selection0_2=103&"+
+		"selection1_0=104&selection1_1=105&selection1_2=106")
+	assert.Equal(t, 303, recorder.Code)
+	recorder = web.postHttpResponse("/alliance_selection/finalize", "startTime=2014-01-01 01:00:00 PM")
+	assert.Equal(t, 303, recorder.Code)
+	alliances, _ = web.arena.Database.GetAllAlliances()
+	assert.NotEmpty(t, alliances)
+	matches, _ = web.arena.Database.GetMatchesByType("elimination")
+	assert.NotEmpty(t, matches)
+
+	// Mark a match as played and verify that the alliance selection can no longer be reset.
+	matches[0].Status = model.RedWonMatch
+	assert.Nil(t, web.arena.Database.UpdateMatch(&matches[0]))
+	recorder = web.postHttpResponse("/alliance_selection/reset", "")
+	assert.Equal(t, 200, recorder.Code)
+	assert.Contains(t, recorder.Body.String(), "matches have already started")
+	alliances, _ = web.arena.Database.GetAllAlliances()
+	assert.NotEmpty(t, alliances)
+	matches, _ = web.arena.Database.GetMatchesByType("elimination")
+	assert.NotEmpty(t, matches)
+}
+
 func TestAllianceSelectionAutofocus(t *testing.T) {
 	web := setupTestWeb(t)