Zenit St Petersburg manager Roberto Mancini has admitted that his side might not be at their best against Celtic after a long lay-off.

The Russian side have travelled to Glasgow for their Europa League encounter straight from a training base in Turkey. They've played a series of friendlies to keep themselves in shape while their league is on winter shutdown.

Zenit last played a competitive game on December 11 and Mancini admitted it was a concern that they were going into a significant match without competitive sharpness.

"We can also have a problem because for us it's the first official game in two months," he said.

"We can't change this situation, we need to do our best if we want to get through."

Mancini was in charge of Inter when they played Celtic at this stage three years ago and he said that Celtic would enjoy a strong home advantage.

"It's always a difficult game here," he said. "Celtic at home is a strong team and also for the supporters that push the team.

"The crowd is incredible.

"Celtic played in a difficult [Champions League] group. I think most teams would lose to PSG and Bayern. It was a tough group and they will be better in the Europa League.

"If we are able to win this game that would be a good result ahead of the second leg next week - but I don't think Brendan would agree with me.

"It is important to try to be offensive and try to score."