Celtic midfielder Neil Lennon believes Lyon will be even tougher to beat than previous Champions League opponents Bayern Munich.
Last season's UEFA Cup finalists were desperately unlucky not to leave the Olympic Stadium with a point a fortnight ago after Roy Makaay's late double.
On the same night Lyon started their Group A campaign with a 1-0 victory over Belgian side Anderlecht to increase the pressure on Celtic.
"I think it's imperative that we don't lose the game," said Lennon.
"Even if we take a point it's not the end of the world because there is plenty of football left.
"We should have got something out of the Munich game and we have to cut out the defensive errors collectively and we've talked about that.
"We are expecting a really hard game and a really different one from the Munich game. They have different styles and I think this will be harder than the game Munich gave us.
"We know Lyon are the French champions and they got a very important victory against Anderlecht in the first game.
"They are a good counter-attacking team and they've got [Giovane] Elber who has been scoring a lot of goals for them.
"Our home form's been pretty good the last couple of seasons but that counts for nothing tomorrow night.
"We have to be on our toes because it's going to be a really proper European game, but we are desperate to win it and we just have to be careful.
"These nights are electric when you come out and hear the Champions League music and the crowd also make it pretty special.
"You can see with the players that the buzz of the crowd gives them a tremendous lift so it's great to have it back again."
The players can often get caught up in the atmosphere and lose their heads but Lennon is confident that his team-mates can keep their cool tomorrow night. Bobo Balde and Didier Agathe have been sent off in recent weeks.
But Lennon insisted: "It's so important to keep your discipline especially at this level. We can't afford to lose players and the players know that."
Lennon has also jumped to the defence of prolific striker Henrik Larsson after he came under fire from Lyon hitman Elber.
The Brazilian accused the Swedish striker of being a big shot in Scotland, but not at the top level - which brought a dismissive reaction from his team-mate.
"Henrik scored three in six games in the Champions League last time, 11 goals [in the UEFA Cup] last year and three in the World Cup finals," sniped Lennon.
"His record is second to none and to anybody on the planet. It's not just his goalscoring, but his contribution to the other players in the team which makes him unique.
"This won't motivate him any more - he just takes it and shrugs it off."