Brendan Rodgers insists discipline is key for Celtic against Lazio in Rome.
The Parkhead side have twice been down players so far this season in the Champions League with Gustaf Lagerbielke and Odin Thiago Holm seeing red away to Feyenoord and then Daizen Maeda being ordered off against Atletico Madrid.
And Rodgers recognises that for his team to pick up the three points in Italy, which they must do to keep their European dream alive, Celtic must keep all 11 players on the pitch.
He said: "I think we learned over the course of the competition against Lazio and other teams when we are 11 v 11, we can really compete on the field.
"Obviously, in the last game when we learned that you need to concentrate right to the very end.
"We looked like the team that was going to win the first fixture and we ended up losing the game which was a big disappointment.
"What is important for us is that we have 11 men on the field, in two matches we have been down to nine men and 10 men and for us at this level that is a big ask.
"We need to keep our players on the field so we can play the level of football we know we can play and have shown and hopefully we can get the breaks in the game."
