Only five points separate the top five after the weekend’s fixtures, with fifth-place Spurs looking to leapfrog the champions having made their best start to a season in the Premier League era.
There are still three unbeaten teams at the end of October for the first time in the division’s history, with City, Chelsea and leaders Liverpool all yet to lose, and Stones believes it is a reflection of the difficulty his side will face in defending their crown.
"You've seen last season where West Brom were having troubles, a new manager [Darren Moore] came in, they went to Old Trafford, beat United and we won the league off of that. I think that shows that any team can beat anyone and not only the top five, top six is strong.
"At any given moment or time, anything can happen in football, but the depth in the league is good. I think it's good because no one ever takes their foot off the gas, especially against the top teams."
City beat Spurs at Wembley on the way to securing last season’s title in record time, at the end of a difficult week that saw them crash out of the Champions League to Liverpool and miss the chance to win the Premier League at home against Manchester United, relinquishing a 2-0 lead to lose 3-2.
"It was a really difficult week," said Stones. "We had a chance to win the league and getting knocked out of the Champions League after the display that we put on at the Etihad, there were a lot of emotions running about to be honest.
“There were a lot of thoughts, a lot quieter in the dressing room, as expected really.”