James Forrest limped away from the champions' 6-1 thrashing of Dundee United on Saturday and is a serious doubt for the match with NK Maribor on Wednesday. Adam Matthews, the Welsh full-back, injured a calf but his fellow defender Jason Denayer believes Celtic can make the most of the reprieve granted when Legia Warsaw were penalised for fielding an ineligible player.
The 19-year-old Belgian, on loan from Manchester City and a scorer on his debut at Celtic Park, said: "We are now all feeling confident about the Champions League. We are going to play with a style of football which we hope will win the tie."
Legia Warsaw scored six goals against Celtic over two legs and there were moments in the thrashing of United that suggested there are still flaws in their defensive play. But Denayer said: "We believe the defence will be far more solid than against Legia. That was the start of the season and the coach is still new and some players are new. But now I think the team know one another better and it will be better in the games against Maribor."
The group stages of the Champions League are two matches away and Denayer said it is "a massive motivation" for the squad. He added: "Ever since I started playing football, it is the tournament I have dreamed about playing in one day. Now I have that possibility with Celtic and I want to take it. I could never have imagined this a few weeks ago, playing for the elite development squad at Manchester City."
Ronny Deila rested Mikael Lustig, the Swedish defender, on Saturday and was noncommittal about Denayer's chances of playing against the Slovenian champions on Wednesday but the defender will be closer to the action than he was when at City.
"What happened with the Legia tie is in the past as far as we are concerned. We are looking to win over two games against Maribor and get into the group stage."
Denayer's delight at his start with Celtic was matched by dismay in the Dundee United ranks. "We are really disappointed," said defender Callum Morris, adding: "It's possibly unrealistic to think anyone can get closer to Celtic in the league."