Jurgen Klopp’s side stormed to the title last term, winning 32 of their 38 league matches to finish 18 points clear of second-placed Manchester City.
Liverpool drew 1-1 with Man City on Sunday to climb to third in the Premier League table, one point behind current leaders Leicester City.
Tottenham, Southampton and Chelsea have also enjoyed impressive starts to the new season but Keane says it will ‘take a lot’ to stop Liverpool.
The Red Devils legend told Sky Sports: ‘We know about Liverpool’s quality, but I look at the body language and mind-set and hunger of teams who have won the league, and I see that so much in this Liverpool team.
‘I still think it’s going to take a lot to stop this team. I know they’re not at their best, they’re grinding out results.
‘But Jurgen Klopp will be delighted with that result. Winning championships is about dealing with setbacks and disappointments and I saw that with Liverpool today.
‘I think the big worry for Man City, they are always brilliant to watch, but it’s the lack of goals. I think it will be very difficult for them to win the league.
‘When you look at their squad, to only have two strikers, the board have to be critical of themselves. They only have themselves to blame. I don’t see Man City winning the league this season.’
Liverpool legend Jamie Carragher added: ‘No team has looked anywhere near their best this season. It’s a strange season with the lack of a pre-season.
‘But I would say there’s more signs of Liverpool getting to their best than Man City right now.
Former Manchester City and England defender Micah Richards, meanwhile, said: ‘Liverpool are a fantastic team.
‘Man City will be close, I don’t know if they will win it. With Van Dijk out, that will cause problems. But Liverpool are still fantastic and I love the way they play.’