That’s the view of Chelsea legend Didier Drogba, who was managed by Mourinho at Stamford Bridge.
Mourinho has won three Premier League titles, split over two spells with Chelsea.
He has not led Manchester United to the league crown, and looks increasingly unlikely to do so this year.
Instead Manchester City, managed by Pep Guardiola, look favourites to retain the title they won at ease last year.
But Drogba, who announced his retirement on Wednesday, believes Mourinho would have been successful at the Etihad.
“I think if you put [Mourinho] at Manchester City, he would have won the league twice, maybe two or three times,” Drogba told the Mirror.
“You get criticism because you set a standard of winning, winning and winning and now you’re not winning or having the same results.
“He is still [at Manchester United]. You have to look at all the managers who were at Manchester United the last few years.
“Being manager after Sir Alex Ferguson is not easy and the finances that they had then are not the same as what they have now.
“People only pay attention to the best and he’s one of the best and that’s why he gets all of this.”
Mourinho has been under immense pressure at Manchester United this season.
The Red Devils already sit 12 points behind leaders City in eighth place in the Premier League table.
And former United midfielder Juan Sebastian Veron believes Mourinho’s side are still struggling from the retirement of Sir Alex Ferguson in 2013.
“They’ve suffered a lot from the departure of Ferguson,” Veron said.
“They’ve never been able to find a direction, while there have been several changes along the way.
“Obviously Manchester City have found an idea, while United have struggled to find an idea or to maintain one since the departure of Ferguson.
“Mourinho is a great coach and manager.
“It’s clear that United haven’t been able to find the right coach since the departure of Ferguson.”