Liverpool beat Manchester City in the teams' most recent meeting at the Community Shield in July
Tenth-placed Liverpool host second-placed City at Anfield on Sunday and are 13 points behind Guardiola's side.
Arsenal are top of the table and Antonio Conte's Tottenham are three points behind City in third.
However, Guardiola said Liverpool "always have been" City's main rivals for the title when asked on Friday.
"If you asked that question with 10 games left I would say I don't think Liverpool can catch the top of the league," he said.
"But being in the position we are now, and with the World Cup, anything can happen.
"I know the quality they have. It has always been a tough game and I don't expect anything else."
City have won four of the past five Premier League titles, with Liverpool beating them to the 2019-20 season by 18 points.
The Reds have pushed City to the final day of the season twice in recent years, including last season when City came from behind to beat Aston Villa 3-2 to deny Jurgen Klopp's side the Premier League title and a chance at the 'quadruple'.
"A few months ago Liverpool were competing for a prestigious situation in English football, four titles, they had more shots, possession, everything in the final and they lost," Guardiola said.
"This is the same team, same manager, things can happen.
"It's part of the nature of the competition. I don't look at good moments or bad moments I analyse as a team always expecting the best of them.
Klopp earlier agreed this weekend's fixture could be a title decider - but "not with us".
The Liverpool manager added: "They helped us to keep going of course in the seasons when we were both running away, this season is obviously different."
During his seven years in charge at Anfield, Klopp's net spend has been around £150million, whereas Guardiola has spent over £500m in 12 months less.
And the German says that Liverpool cannot match City in the transfer market so have to find other ways to challenge.
"Nobody can compete with City in that," Klopp added.
"You have the best team in the world and you put in the best striker on the market [Erling Haaland], no matter what it costs, you just do it.
"What does Liverpool do? We cannot act like them. It is not possible. There are three clubs in world football who can do what they want financially. It's legal and everything, fine, but they can do what they want.
"We have to look at it [and say] 'We need that and we need that and we have to look here and make it younger, and here a prospect and here a talent'.
"That is what you have to do. And you compete with them. You have to compete with them. It is not a problem at all for me, it's like it is.
"I heard now that at Newcastle somebody [sporting director Dan Ashworth] said 'There is no ceiling for this club'. Yes, he is absolutely right. There is no ceiling for Newcastle. Congratulations. But some other clubs have ceilings."
-- Courtesy of BBC Sport