Jamie Redknapp believes that David Moyes will receive a huge confidence boost and the fans will be back ons his side if he can take Manchester United to a win over their bitter rivals this weekend.
With a tough start to the Premier League season in which United have faced Liverpool and Chelsea already, Moyes has already had to undergo some difficult tests while attempting to fill Sir Alex Ferguson's shoes.
Their match-up with City this weekend comes on the back of having to defend their transfer window dealings to fans after landing only Marouane Fellaini in the summer and Redknapp has argued that a win this weekend will be even more important if Moyes hopes to appease the supporters.
"Moyes - like Manuel Pellegrini - can really lay down a marker at his new club by winning the Manchester derby; that will really foster the fans' belief," he told Sky Sports. "Both managers want to prove that they were the best choice for the job and the best way to do that is by winning the match that means most to the supporters.
"If Moyes achieves the feat it will give him so much confidence, but he's under a lot of pressure after losing at Anfield and the last thing he needs is to lose at the Etihad.
"The longer he goes without winning a big game, the more the pressure will build. But if United beat City on Sunday he will win over the fans who are still mourning Sir Alex Ferguson's retirement."
Replacing Ferguson was always going to be a big ask for Moyes but after the manager publicly identified Cesc Fabregas as a target in the summer transfer window, and then failed to land any big names other than players who had featured for him at Everton, fans became more uneasy about his position.
With the Scot displaying limited European experience it was certainly a boost for United to come out in their first Champions League match and beat Bayer Leverkusen 4-2. But after drawing with Chelsea and losing to Liverpool in the league they'll be keen to show they are still capable of winning the big games even without Ferguson in the dugout.