Kristoffer Ajer is relishing the expectation levels placed upon him at Celtic.

The 20-year-old has become a vital part of Brendan Rodgers' side, keeping three clean sheets in their Champions League qualifiers so far.

The Celtic boss praised the young defender for his performance in Norway against Rosenborg and Ajer said he welcomes the pressure of the high-profile encounters.

He said: "That's what you want as a footballer.

"You train every day to have expectations on your shoulders.

"To perform and keep a clean sheet [away to Rosenborg] it was a fantastic feeling.

"I think every single game you play for Celtic you have expectations to win.

"I think it's a really healthy environment to be in at Celtic, there's a big game coming up every few days and you have to be ready for that.

"That really develops you.

"You don't have the opportunity to rest and think about the last game, you've got to look forward and there's already a game coming."

Celtic welcome Greek champions AEK Athens to Celtic Park on Wednesday in the first leg of their third round qualifier.

Ajer said he is expecting a difficult encounter but said that is a given as he believes the calibre of teams is always going to be high at this level of competition.

He added:"When you play these games, they will always be tough games. We know that AEK are a fantastic team.

"When you play for Celtic it's a target to get to the Champions League.

"I think when you play for Celtic you always want to be in the Champions League, that's what we aim for.

"We know it will be tough, we played Alashkert, we played Rosenborg and now we play a great team.

"It's hard but it's what you expect, it's the Champions league, it's the best teams in the world."