diff --git a/django/contrib/admin/views/decorators.py b/django/contrib/admin/views/decorators.py
index 3039daadb1..c27b2e7427 100644
--- a/django/contrib/admin/views/decorators.py
+++ b/django/contrib/admin/views/decorators.py
@@ -84,18 +84,13 @@ def staff_member_required(view_func):
             message = ERROR_MESSAGE
             if '@' in username:
                 # Mistakenly entered e-mail address instead of username? Look it up.
-                try:
-                    users = list(User.objects.filter(email=username))
-                    if len(users) == 1:
-                        user = users[0]
-                    else:
-                        # Either we cannot find the user, or if more than 1 
-                        # we cannot guess which user is the correct one.
-                        raise User.DoesNotExist()                        
-                except User.DoesNotExist:
-                    message = _("Usernames cannot contain the '@' character.")
+                users = list(User.objects.filter(email=username))
+                if len(users) == 1:
+                    message = _("Your e-mail address is not your username. Try '%s' instead.") % users[0].username
                 else:
-                    message = _("Your e-mail address is not your username. Try '%s' instead.") % user.username
+                    # Either we cannot find the user, or if more than 1 
+                    # we cannot guess which user is the correct one.
+                    message = _("Usernames cannot contain the '@' character.")
             return _display_login_form(request, message)
 
         # The user data is correct; log in the user in and continue.