Kevin De Bruyne scored the opener on the 15th minute, capitalising on some poor defensive work from the hosts, while Kelechi Iheanacho scored City’s second of the afternoon before the break.
Zlatan Ibrahimovic pulled a goal back for the Red Devils on the stroke of half-time following an awful mistake by Claudio Bravo, but the visitors held on to seal the victory.
But what did we learn from the 90 minutes?
Scroll down to see the five things and don’t forget to leave a comment with your thoughts at the bottom of the page.
Daley Blind’s mistake shouldn’t come as a shock
Daley Blind isn’t a natural centre-back and, as a result, it shouldn’t come as a surprise to anyone - particularly Jose Mourinho - that the Dutchman makes mistakes from time to time.
Because he’s such an intelligent footballer, Blind’s positioning is often spot-on. His distribution is good, too.
But he was far too hesitant in the moments before Kevin De Bruyne scored the opener this afternoon and it cost his team dear.
Expect to see Chris Smalling alongside Eric Bailly over the coming weeks.
De Bruyne can become the league’s best player
Kevin De Bruyne was the Manchester derby’s star man.
The Belgium international scored the first goal of the afternoon on the 15th minute and hit the post in the move which led to Kelechi Iheanacho doubling the visitors’ advantage.
Manuel Pellegrini convinced City to pay £55 million for the former Chelsea winger - but that fee has looked a relative bargain on multiple occasions over the past 12 months.
De Bruyne has the potential to cement his status as the Premier League’s best player and he’ll surely be in the running for the PFA’s Player of the Year award come April.
Don’t judge Bravo too soon
Yes, Claudio Bravo had a bit of a nightmare today, but making his City debut in the Manchester derby at Old Trafford was always going to be a big ask for the 33-year-old.
The experienced Chile international is a top goalkeeper - his 10 years in La Liga with Real Sociedad and Barcelona has provided more than enough evidence to come to that conclusion - and he’ll prove that over the coming weeks and months.
Today proved that even experienced players can be overawed by the occasion.
Pogba failed to impose himself today
At £89 million, Paul Pogba can’t afford to have games where he slips under the radar.
The price tag isn’t his fault, obviously, but the Frenchman will be disappointed with his individual performance today.
Pogba loves a bit of social media but should probably avoid Twitter for a few days, given the reaction on the social media website.
Rashford has to be starting for Man Utd
Marcus Rashford made an instant impact after coming on with the ineffective Jesse Lingard at half-time.
Just as Sam Allardyce should have called the teenager up to the England senior side during the international break, Jose Mourinho should have started him this afternoon.
Rashford was full of confidence after his mid-week hat-trick for England Under-21s against Norway and could have made an even bigger contribution had he played from the start today.
What did you make of the Manchester derby? Have your say by leaving a comment below.