RONNY DEILA last night insisted Celtic fans were happy with their team’s domestic form and only European results have disappointed them.

But SportTimes understands highly-rated Northern Ireland boss Michael O’Neill is top of a list of potential successors to the under-pressure Norwegian if the Parkhead board opt to change their manager.

Deila tonight faces what is arguably the biggest match of his Celtic career when he takes his team to Aberdeen.

A win for the home side would reduce the gap at the top to three points and following hard on the heels of the cup defeat to Ross County, even the most patient supporter would start to ask questions.

Celtic not winning the league is unthinkable and would cost Deila his job, which might well be Celtic’s decision even if he can make it five in a row - and a story in a Belfast newspaper insisted former Dundee United and Hibernian player O'Neill would be a candidate.

For really the first time, some sections of the support turned on Deila at Hampden at the weekend as another Treble came and went, but the Celtic manager insisted the fans were content enough with how this season was going.

Deila said: “I think domestically the supporters are not so disappointed. We won the double last season and in the league we have done well, no-one can say we haven’t, comparing the history as well.

“Europe has not been good enough. That’s where the disappointment lies. That’s what we are working hard to change.

"Nothing should be a better feeling than to change that around and hopefully get into the Champions League next year; that’s in my head all the time.

“But it’s a long way to there, and it’s about always working to improve and to know your players and get better and get the team ready.

"There are so many things that can lead up to hopefully sitting here in September and doing some high-fives and hopefully everyone is happy.”

Sources close to O’Neill told SportTimes that the 46-year-old, while not touting himself for the job, would talk to Celtic if Deila left and the club looked across the Irish Sea for his successor.

It is understood that both Martin O’Neill and Neil Lennon would firmly back the appointment of their fellow countryman, who has taken the Province to the Euros in France this summer, their first major championships since 1986, .

An obvious problem would be that O’Neill’s hands would be full in France – there is no way he would quit before the finals – which is the time Celtic would begin preparations for their next attempt on the Champions League.

However, he is well known for having an encyclopaedic knowledge of European footballers which could help smooth the transition.

O’Neill’s reputation has never been higher. His unfancied Northern Irish side not only finished top of their group, but he has had a huge say in a revolution in youth football in his country.

The Northern Irish FA are in the process of offering him a four-year deal, but there will be a clause inserted into it which would allow him to talk to a club if he so wished.

Deila is still there, of course, and once again stated his belief that his position was under no immediate threat.

He said: “I really believe the club has full faith in me, that the players are behind me. I really believe that. But of course things change if you don’t win games.

“So you can’t say ‘I’m going to be here next season’, you never know. If I start to lose all the games then of course I won’t be here next season. But I am so confident that we are going to have a good season and win the league.

"We want to win everything but the main target is the league so that we can again qualify for the Champions League. If you win the league is that the deciding factor, winning the league entitles you to carry on?”

One thing Deila does have going for him is that every request he has made in terms of improving things behind the scenes, such as the medical side, have been granted by the board.

Deila said: “You have to see behind the result as well, of course. For you, you have to judge on what you see in the results but people inside the club see more than that and they have to see the whole picture.

"There are so many aspects to it, so many aspects that I get evaluated on.”