Ambrose was at fault for both goals Celtic conceded against their Turkish opponents, as they threw away a two-goal advantage in the contest, and his performance opened him up to a lot of criticism from supporters.
However, Deila has protected the Nigeria international, stating that his overall display was a good one - despite his mistakes.
“I think he, if you look at the overall game, performed well, but as a defender you need to concentrate for 90 minutes and that is the biggest challenge Efe has," he said.
“He can play well for 88 minutes, but then sometimes he makes an easy mistake like he did tonight. As a defender you must have concentration for 90 minutes.”
Ambrose has always had a tendency to make errors during his career at Celtic, with his concentration levels often lacking.
The 26-year-old has been with the Bhoys since 2012, and he has always had a fragility to his defending, so Deila will have his work cut out if he is to eradicate errors from Ambrose's game entirely.
It could be that the best course of action is to drop him from the Bhoys' first-team for the time being, as Celtic have plenty of other options in defence.
Celtic's draw against Fenerbahce means that they have two points from their first two Europa League games, with Molde their next opponents in continental competition.