Ronny Deila believes Celtic will face a Motherwell side performing at as much as twice their normal capacity when they travel to Parkhead for their Premiership clash on Sunday.

The Norwegian took over as Hoops boss from Neil Lennon in June and has only been in charge for five domestic matches.

However, the former Stromsgodset boss claims he has already noted a propensity for opponents to lift their game against the Scottish champions.

"From what I have seen so far in Scotland, teams against Celtic are 50 to 100 per cent better than they were in the last game," he said.

"It is like a cup final to them and that is why every game is very difficult in Scotland.

"It doesn't surprise. I have been an underdog myself. When you meet the big teams you have nothing to lose, you just go for it.

"It is fantastic to win those games so I understand it is huge for other teams to play Celtic, especially when they come to Celtic Park with the crowd and the fans we have there, it is a lot of motivation.

"Motherwell is a task that we have to take very seriously. But still, we are at home and we will do everything we can to put in a good performance and win the game."

Celtic go into the game in confident mood following a decent start to their Europa League campaign.

The Hoops drew 2-2 with top seeds Salzburg in their opening Group D clash in Austria on Thursday night.

Deila will try to balance domestic expectations with European aspirations.

He said: "We will take one game at a time and see where it ends.

"To win the league is the most important thing but it is also a huge thing to go far in the Europa League."

Deila has fitness concerns over Stefan Johansen, who picked up a leg injury in Austria.