The Blues have won 14 and drawn one of their opening 15 matches in all competitions, with the 3-2 win at West Brom on Saturday maintaining their five-point lead at the top of the Premier League table after 10 games.
Some pundits believe Pep Guardiola’s squad is the strongest assembled since the Premier League began but De Bruyne, who has been in form this season, says emulating Arsenal’s ‘Invincibles’ is too difficult given the current level of competition in the English top flight.
“To go unbeaten? Well, it’s very hard,” the Belgian said.
“I don’t think it will be possible. The level of competition is so high, in every team. It’s not like, with all respect, 10 or 15 years ago where you have a couple of teams that won’t win against the top teams.
“Now, every game is hard and you need to be mentally there.
“And with the Champions League and all the cups, there will be a game where maybe we are a little bit less and maybe lose. But as long as our form keeps going, it’s good.”
City are currently unbeaten in 21 matches in all competitions stretching back into last season, the longest sequence in the Club’s history.
Their last eight Premier League games have all been won with an aggregate score of 32-5, and their 28 points from 10 games with a goal difference of +29 represents their best-ever start to a Premier League season.
West Brom made life difficult for City at Saturday but Guardiola’s side managed to complete 844 passes - the most since Opta began recording data in 2003 - and De Bruyne says he felt City were always dominant.
“It was a hard game but we were in control throughout,” he said.
“Obviously, in the end it looks more tight than it was but I think the way we did it was the same as always. Maybe we could have scored more goals but in the end it was a good victory again.
“We feel good and we control the game quite well. Obviously, they will try to put on more pressure but we went over the pressure and found options up front.
“Maybe we weren’t clinical like other games but we scored three, which is good.”
West Brom became only the second side this season to score twice against City.
They provided a physical threat, with a direct style that was in stark contrast to City's possession-based game.
De Bruyne admits they are difficult to play against but says he is pleased with how well City coped with the threat.
"At what they do, they are very good," he said.
"It’s very tough for us because obviously we are not the biggest or most physical team and they play with a lot of long balls, but I think we coped quite well.
"I don’t think we got a lot of chances against us, except the goals and a header at the beginning of the second half. That means we defended quite well.
"We got two goals against, it happens."