KRISTOFFER Ajer today told Brendan Rodgers he can cope with the biggest test of his career so far if he gets the nod to play for Celtic in their Europa League last 32 clash with Zenit St Petersburg.

The Parkhead club conceded two sloppy goals in their William Hill Scottish Cup fifth round tie with their Glasgow rivals Partick Thistle at home on Saturday.

And only a brilliant tackle from Kieran Tierney in injury-time prevented Ryan Edwards netting an equaliser for Alan Archibald’s side and forcing a replay.

But Ajer, who played in central defence alongside Jozo Simunovic in the 3-2 win, has revealed he watched the game back immediately afterwards in a bid to learn from his mistakes.

The 19-year-old, who was outstanding in the 0-0 draw with Rangers back in December, is confident he can help the Scottish champions keep a clean sheet against their Russian rivals on Thursday night.

“I think the gaffer has a squad here that really knows their job,” he said. “Everyone is ready when they’re called upon. If I get the chance on Thursday I will be ready.

“I feel when I play for Celtic here I’m 100 per cent focussed in every single game. For me, being 19 years old, every single game is big. It won’t make a change who we play against or what day it is. I’ll always try to do my best. We defend as a team every time. We don’t want to mistakes."

Ajer added: “I went home on Saturday and watched the full Thistle game again. I do that for every game. That’s how I work. I look at the details, I look at the goals. I look at when I’m with the ball to find easier solutions next time. That doesn’t change from game to game.

“I will sit until the evening now but when you play games I think that’s a big part of the game. You must watch it and learn from your mistakes and what you did well too. I go back and forth to learn things then I have a chat with the staff on the Monday when we meet again. It’s good and it helps me a lot.”

Ajer, who picked up an ankle injury in the 1-0 defeat to Kilmarnock nine days ago and took painkillers to play against Thistle at the weekend, is confident he can form a solid central defensive partnership with Simunovic against Zenit if he is selected.

“I’ve been here in this club for almost two years and I’ve played with so many defenders that its helped me a lot,” he said. “We talk a lot together so it doesn’t change things too much. Everyone knows the job when they come in. So it’s not too different.

“Zenit are a good team and we’re really looking forward to that challenge on Thursday. We respect them a lot, we’ve seen a lot of them and we’ll see a lot more of them in the coming days so we’ll be ready for that game.

“We haven’t watched too much of Zenit already. We take one game at a time and I will look at all the attacking players from Zenit and how they play over the next few days.”

Ajer is hopeful James Forrest, who scored the first hat-trick of his professional career in the win over Thistle on Saturday, can reproduce the form he showed at the weekend against Roberto Mancini's side on Thursday. "James has been brilliant the whole season," he said. "Scoring three goals proves how good a player he is."