Pep Guardiola has said he still believes Liverpool will be Manchester City's main title challengers this season and has told his players they must step up at Anfield on Sunday after being "soft" in their last two games against Jurgen Klopp's side.

Klopp has said Liverpool are not in the race to lift the Premier League trophy after winning just two of their first eight league games.

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City are already 13 points ahead of Liverpool in the table but Guardiola says it's too early to write them off after coming so close to winning an unprecedented quadruple last season.

"Always have been, always it is, and will be [the main challengers]," Guardiola told a news conference on Friday.

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"I know the quality they have, the character.

"Two months ago Liverpool were fighting for an unprecedented situation in English football, fighting for four titles. They won two and lost [the league] by one point

"They could have achieved something that's never been achieved by an English team. This is the same team, same manager and players."

City have lost their last two games against Liverpool -- the Community Shield in July and last season's FA Cup semifinal.

Guardiola accused his players of being "soft" in both games but is expecting a better performance on Sunday.

Erling Haaland is fit after he sat out the 0-0 draw with Copenhagen on Tuesday but John Stones, Kyle Walker and Kalvin Phillips are still out.

"Maybe in the last two games we were a little bit soft," Guardiola said.

"You have to win duels. When they push you, you have to push, you have to be there. The semifinal in the FA Cup was tough, after an incredible effort in the Champions League, and in the Community Shield we were not ready.

"They were one base higher, you cannot do that against this team."