diff --git a/app/controllers/contests_controller.rb b/app/controllers/contests_controller.rb
--- a/app/controllers/contests_controller.rb
+++ b/app/controllers/contests_controller.rb
@@ -17,6 +17,14 @@
     end
   end
 
+  def clear_stat
+    user = User.find(params[:id])
+    if user.contest_stat!=nil
+      user.contest_stat.destroy
+    end
+    redirect_to :action => 'user_stat'
+  end
+
   def clear_all_stat
     if not Configuration.indv_contest_mode?
       redirect_to :action => 'index' and return
diff --git a/app/models/user.rb b/app/models/user.rb
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -20,7 +20,7 @@
   has_many :test_pair_assignments, :dependent => :delete_all
   has_many :submission_statuses
 
-  has_one :contest_stat, :class_name => "UserContestStat"
+  has_one :contest_stat, :class_name => "UserContestStat", :dependent => :destroy
 
   belongs_to :site
   belongs_to :country