That’s according to ex-United coach Rene Meulensteen.
After years of domination from the Red Devils, the Sky Blues are now the noisy neighbours around Manchester.
United have finished in the top four just once since 2013, also winning a handful of trophies.
“I would have done everything in my power to bring Pep Guardiola”
And their decline over the last six years all points to the departure of one man – Sir Alex Ferguson.
Ferguson brought his trophy-laden 27 years at the Old Trafford helm to a halt at the end of the 2012/13 season.
The Scot was immediately replaced by fellow countryman David Moyes.
In the same summer, Pep Guardiola joined Bundesliga giants Bayern Munich.
But Meulensteen, who worked for years as a coach under Ferguson, thinks United bosses missed a trick by not going after Guardiola.
Speaking after last night’s derby, the former Fulham manager revealed how Guardiola would have been a great fit at Old Trafford.
“If Sir Alex Ferguson would have still been in charge I think there would have been two or three or probably four changes,” Meulensteen told Stadium Astro.
“Players would have left the club and again you would have just carried on.
“I think that was the biggest thing for me.
“I would have done everything in my power to bring Pep Guardiola to Manchester United.
“I think his philosophy is so close in terms of the attacking way to play as we always wanted.”