Manchester United defeated Manchester City 2-1 at the Etihad Stadium courtesy of a brace from Marcus Rashford.
Rashford opened the scoring for the visitors when he converted from the spot after he was fouled by Bernardo Silva.
The England forward has scored 13 goals in his past 14 games for club and country.
Anthony Martial extended Manchester United lead with a tidy finish to give United a 2-0 lead heading into half time.
City had various penalty shouts which was turned down by the referee.
Nicholas Otamendi reduced the deficit for Manchester City five minutes from time but it was too little too late as United held on for a vital win.
Manchester City goalkeeper Ederson saved from Daniel James, Marcus Rashford to ensure a respectable scoreline for the defending champions.
Manchester United’s best results this season have come against the big teams.
Ole Gunnar Solskjaer described the victory as memorable
“We will remember this one – we look so dangerous when we get he ball and go forward against arguably the best team in the world.
“They are an unbelievable team and to get a result and defend like we did and create as many chances… we should have been three or four up but for some good goalkeeping.
It’s hard to take the ball off them. They can football teams to death but with the pace and threat we have, we look dangerous every time we go forward.
Manchester City are now 14 points behind Premier League leaders Liverpool.
Liverpool defeated Bournemouth 3-0 away from home to go 11 points clear, Chamberlain, Keita and Salah were the goalscorers.
Tottenham spanked Burnley 5-0 thanks to goals from from Harry Kane who scored a brace, Lucas Moura, Moussa Sissoko and Son who scored a contender for goal of the season award.
Watford and Crystal Palace played out a goalless draw.