Ambrose is suspended for tomorrow’s game against Hamilton following his injury time red card in the goalless draw against Hearts last week.
Deila said: “He has made mistakes before and he is an experienced boy who has been to big games and to the World Cup.
“He was very sorry about the mistake on Thursday but every player makes mistakes. He needs to move on from it, learn from it and follow up the progress he has been making because 98 percent of his game against Fenerbahce was very good.
“He has played a lot of games under me. If I see people develop, they have my confidence. But if they make the same mistakes over and over again, then we have issues.”
While Deila will not shirk from using Ambrose, he has acknowledged that similar errors will give him a problem.
He added: “With Efe – and I say this all the time to him – his biggest task is concentration, One year ago he was making more mistakes than he does now. He is much calmer on the ball and he doesn’t take so many risks. But still he has issues with easy mistakes that we have to get sorted.
“He is only 26 years old and also off the pitch he is a very good person to have in the squad. He always works 100 percent in training. He always stands behind the team, supports his team-mates and that is very important. He knows what he has to work on and he enjoys working and seeing the improvement.
“Now he is very disappointed but he will get over it and move on.”
Meanwhile, Deila was coy on reports linking him with a move for Leke James, a 22-year-old Nigerian who is playing for Aelesund in Norway. The player had tweeted to say that he had been watched by Celtic, prompting speculation that he was preparing for a move to Glasgow.
Deila admitted: “I watch everyone in Norway, so he can say that. I’ve seen his matches, but also the others in Norway.
“He’s a good football player, but we haven’t been close to doing something there.”