RONNY Deila last night warned Efe Ambrose he has to learn to concentrate for 90 minutes after the centre half's errors cost Celtic victory in their second Europa League group game against Fenerbahce at Parkhead.

Deila’s side stormed into a two goal lead against Vitor Pereira’s team during a stunning four minute spell in the first half of their second Group A outing thanks to strikes from Leigh Griffiths and Kris Commons.

However, poor defensive play from Ambrose allowed Brazilian substitute Fernandao to score for the Turkish club on either side of half-time and the match finished up 2-2.

Deila’s side failed to qualify for the Champions League group stages this season after surrendering a two goal lead in the play-off against Malmo of Sweden.

However, the Norwegian coach denied that his side had a problem protecting a lead in Europe and urged Nigerian defender Ambrose to focus for the duration of the game in future.

“I think if you see the overall performance, when you are defending you need to keep concentration for 90 minutes,” he said.

“That is the biggest challenge that Efe has. He plays very good for 88 minutes. But he sometimes has some easy mistakes. Today was one of them. As a defender, you have to keep concentration for 90 minutes.”

Asked about his side’s failure to protect a two goal lead in Europe once again, Deila said: “It is obviously a concern. But it is better to do that and go under and then stay under.

“You can see it in different ways. I think we had very good control of the game in the first half. You can’t coach against these individual things.

“In the second half we were a bit too deep in the start. I made some changes and I think we get a bit more into the game. We kept the ball more. When we believe in ourselves and we dare to play football then we are a good team.

“That is what we need to do more. We need to go for it and believe in our system and believe in ourselves on the ball. We have to defend as high up the pitch as possible and we need to keep the ball more.”

Deila, whose side has now drawn their first two Europa League group games against Ajax and Fenerbahce 2-2, singled out Scott Brown, James Forrest and Kieran Tierney, who made his European debut aged just 18, for special praise, after the game.

He also back Griffiths, who took his tally for the season to 11 with his goal, to score for Scotland in their Euro 2016 qualifier against Poland at Hampden next Thursday if he is given the nod by manager Gordon Strachan.

He said: “It would have been better if we had won. But we have to take the positive things. I was very happy with Kieran today. He had a very good debut. I think Scott Brown was fantastic in the midfield. He worked very hard. James Forrest’s work rate was impressive. What a difference there is in him compared to a year ago. There are positive things there.

“I think Leigh is in very good form. He is scoring goals all the time and that is positive. He is in the Scotland squad and is going to be available for the matches. I have to say that I don’t know too much about the other strikers with Scotland, but I do know Leigh is on fire and scores goals in almost every game now. He has a good opportunity I think.”