The defender's first-half mistake allowed Argentina striker Carlos Tevez to score the winning goal for Roberto Mancini's men at Villa Park.
Defeat kept Villa in the relegation zone, but Lambert insists the Republic of Ireland international can only learn from his mistakes.
The Scot told The Sun: "He's all right. I spoke to him on Tuesday after Monday's game.
"He'll be better for it in a stupid, roundabout way. It would be different if he was making mistake after mistake.
"He tried something because his confidence was extremely high with the way the game was going. But I'm sure he won't try anything like that again."
Lambert says the club must now 'fight for every point' with just 10 matches left to secure their top-flight status.
"The players are in a war now - and they have to see it through," said Lambert.
"They're going to have to fight for every point.
"You don't realise what you have got until it's not there, that's one thing I would say. You have to earn the right in football, it's no walk in the park.
"We know it's in our capability to do it, that's the thing I've got. To be fair, since I've been here, I've never encountered any tension among the players."