Celtic manager Neil Lennon admits Kristoffer Ajer is a major doubt for Ibrox this weekend but played down fitness concerns over Odsonne Edouard.

Both players went off as Celtic stormed into the Europa League group stages with a 4-1 victory over AIK in Stockholm, less than three days before they face Rangers.

Ajer – Celtic's most consistent defender this season – limped off with a groin strain inside 15 minutes to add to Lennon's defensive woes, with Hatem Abd Elhamed and Jozo Simunovic missing the play-off second leg through injury.

And Edouard, Celtic's first-choice striker, went down after feeling his hamstring and signalling that he wanted to come off.

Lennon told Celtic TV: "Kris will be a worry. He's a major doubt for Sunday.

"Odsonne is fine, it's just cramp. We will wrap him up in cotton wool and he should be OK. He is playing brilliantly, leading the line brilliantly, a really important player for us."

Celtic otherwise had an untroubled evening as they built on their 2-0 first-leg advantage.

James Forrest netted a brilliant counter-attack goal in the 17th minute and Mikey Johnston forced an own goal from the AIK goalkeeper after superb wing play 60 seconds after Sebastian Larsson levelled from the penalty spot.

Christopher Jullien and substitute Lewis Morgan both netted their first Celtic goals from close range in the closing stages after the visitors had controlled the second half.

Lennon said: "Outstanding, the whole team, the subs who came on made a contribution.

"I couldn't have envisaged us playing so well. Going forward we were a dream at times. To score four goals away from home, and it could have been more, is brilliant.

"We looked strong, we played some brilliant football, we defended resolutely when we needed to.

"I can't ask for any more from the players at the minute. Apart from one half against Cluj we have made an outstanding start to the season and we have got some big games now to look forward to.

"The first goal was a beautiful goal, great interplay from Jamesy and Odsonne, and an outstanding composed finish. Jamesy was magnificent in everything he did, on the ball, off the ball.

"The front four, (Ryan) Christie, Johnston, Odsonne, and Jamesy, looked very powerful, looked a threat, looked fit. And we kept going, there was a real thirst for goals, which is the way we want to play."

Lennon will now try to make sure his players are fully ready for their first derby of the season.

"There's no respite," he said. "We will get them in on Saturday, obviously they will be off Friday and get them well rested and recovered.

"But psychologically that should give them a huge boost going into Sunday."