Wigan Athletic manager Steve Bruce refused to condemn Titus Bramble even after the defender's error gifted Everton their opener in Sunday's 2-1 victory at the JJB Stadium.
The gaffe-prone former Newcastle United stopper allowed Andrew Johnson to fire the Toffees into a 39th-minute lead before Joleon Lescott doubled the advantage before half-time.
Bramble's mistake was his second of the season after his howler handed Manchester City an early goal in Bruce's first game in charge in November.
However, Bruce backed the defender to iron out the errors in his game with hard work on the training ground.
"Unfortunately for Titus, he made a horrible mistake that has cost us badly," said Bruce.
"I have to say he has been terrific since I came through the door, even though he got my career here off to a terrible start in the game with Manchester City after just 20 seconds.
"The boy has all the attributes to be a top player, but the one thing he has to do is work on his concentration levels.
"When you're playing at the back you get judged, and the great ones and good ones don't often make mistakes.
"Unfortunately for Titus, he makes a mistake and he gets punished badly, so we'll keep working on him.
"There's nobody more disappointed than him, but if we can increase the concentration levels, then we'll iron out the mistakes.
"Usually you get better with age and experience and improve as a defender, and let's hope he does."