Manchester United climbed to fifth on the league table with a 1-0 victory over West Ham United at Old Trafford on Sunday.
Before the weekend's Premier League action, Man City boss Guardiola named Manchester United and Newcastle United as potential challengers for the title.
The Red Devils have not won the Premier League title since Sir Alex Ferguson's final season in charge in the 2012/2013 campaign.
Under new manager Erik Ten Hag, Manchester United begun this season on a poor note, losing to Brighton and Hove Albion and Brentford in their opening two games but have since strung together seven wins in their next ten matches, only losing to Manchester City in that time.
Ten Hag reckons his side are getting better but still feels there is still a long way to go before they can match the Premier League champions.
"I think it's a little bit too quick to see," Ten Hag told Sky Sports. "Second half, I have to be critical.
"I also said to the players we have to think better, but the spirit we have is fabulous, and I also think we have the qualities to score goals.
"We have attacking football, we have to improve that, but if we keep going, I think we are in the right direction.
"To be a threat to them [City]? We have a long way to go."
