The Scottish champions were 2-0 up and on course for their first victory in Group A through goals by Leigh Griffiths and Kris Commons before a nightmare error by Ambrose let Brazilian striker Fernandao in to pull one back for the Turkish side just before half-time. The Nigerian defender looked culpable again when Fernandao eluded him to head in Fenerbahce’s equaliser three minutes into the second half.
With Molde and Ajax drawing 1-1 in Norway in the other Group A fixture, Celtic remain firmly in contention to qualify for the knockout phase of the tournament.
But Deila recognised an opportunity lost for his team and has urged the much-criticised Ambrose to improve his focus on the big occasion.
“If you see the overall performance, when you are defending you need to keep concentration for 90 minutes,” said Deila. “That’s the biggest challenge Efe has. He plays very good for 88 minutes but sometimes makes some easy mistakes. The first goal was one of them. As a defender, you have to concentrate for 90 minutes.
“Yes, of course (it is a missed opportunity to win). We played well in the first half and went 2-0 up. It was important to keep that lead into the break, then I thought we would have had a very good chance in the second half
“But we conceded an easy goal and that gave them energy and put us on back foot. They had us for 15 minutes in the second half. They didn’t create a lot but scored from a set play. It’s disappointing they scored with the two chances they had.
“We finished the game quite well without creating a lot. I’m disappointed we didn’t win but happy we got a point and the group is still very open.”
Celtic also let a winning position get away from them when they drew 2-2 away to Ajax in their opening Group A fixture.
“That is always a concern,” said Deila. “But it is better to do that than to go under and stay under. We had very good control of the game in the first half but you can’t coach these individual things.
“We were too deep at the start of the second half. You can see we believe in ourselves. When we dare to play football, we are a good team
“We need to play our system and defend as high up the pitch as possible. We need to keep the ball more. We finished the game well with some good passing and crossing in their half.
“The draw between Molde and Ajax is a very good result for us. The group is very open, it is in our hands and we can do it. There are a lot of possibilities.
“Of course it would have been better if we’d won but we have to take positive things from tonight.
“I just want to see us braver on the ball. That’s going to be the key to our future.”