Victory for Jurgen Klopp's team would open a nine-point lead with 12 games played, and in the context of last season's relentless title race, that looks huge.
Asked whether it is all over if they lose, Guardiola said: “I don't know, what happens if we win?
“I think in November it is never over. That is my point - I know what is going to happen if we lose, people will say it's over but there are a lot of games to play and my experience in sport is that you have to fight until the end.
“(Whether) we are going to win the Champions League or not, your favourite question to me, I don't have the answer. I'm sorry.
“I don't know if it will be over – it will be more difficult as one season they've lost one game and this season they are unbeaten.
“So you have to imagine they are not going to lose too many games but the season is long a lot of games and situations that can happen."