Rooney shows that last weekend's loss was just a blip: Man U 2-1 Man City
A 78th minute goal by Wayne Rooney provided a win that strengthens Manchester United's place at the top of the Premier League, and ruins Man City's title hopes.
It was an important Manchester derby. For Mancini's Man City it was the biggest game of the season - a chance to show they're still in contention and to lessen their local rival's lead at the top of the table.
For Manchester United it was the chance to show the likes of Arsene Wenger, who had predicted that the Red Devils would find it tough to recover from their defeat last weekend by strugglers Wolves, that normal service - which involves winning - had been resumed.
Nani opened the scorecard just before half time, powering in a shot after being fed the ball by Ryan Giggs, to give the home team a 1-0 lead at Old Trafford going into the break.
It looked like being enough until 20 minutes into the second half when what was a pretty poor cross from Shaun Wright-Phillips ended up with Edin Dzeko who slammed a shot into David Silva's arse and into the corner.
In the end this odd goal wasn't enough, though.
With just over 10 minutes to go, Nani delivered a cross that resulted in a stunning overhead kick by Rooney from 12 yards into the top corner.
That really was enough to seal a United win.
Final score: Manchester United 2-1 Manchester City.