City dropped points on Sunday after a dramatic 3-3 draw with Tottenham at the Etihad, despite leading the game twice.
Meanwhile Liverpool sensationally beat Fulham 4-3 in stoppage time earlier in the afternoon, while Arsenal held on to beat Wolves 2-1 on Saturday.
It means that the Gunners retain their place at the top of the Premier League table, while the Reds have leapfrogged the Citizens into second place.
After 14 games, just three points separate the top three, with Aston Villa, Spurs and Newcastle not too far behind.
Having won the last three titles, City naturally remain the favourites to win a record fourth Premier League in a row but Manchester United legend Keane believes the others are better placed to triumph now.
‘I certainly wouldn’t bet against Man City, but I am starting to become doubtful about City winning that title,’ Keane told Sky Sports.
There’s a reason it hasn’t been won four years in a row because keeping those levels up, that hunger, desire, you get a few injuries, some of the top boys coming off it.
‘But certainly Arsenal and Liverpool I’m looking at, especially Arsenal with the strength and depth they’ve got and the experience of last year.’
It was a great result for Tottenham given the opposition and the terrible injury crisis they’re enduring, though it still means they are winless in four games.
Now fifth and six points off Arsenal, Keane believes that just finishing in the top four will be a huge challenge for Spurs, adding: ‘They need to get some of their better players back.
They’ve had a decent start to the season, there’s been a sticky patch over the last few weeks, but they’ve played some decent stuff. Get one or two [players] in during January as well.
