Ole Gunnar Solskjaer's Manchester United defeated Pep Guardiola's faultless Manchester City in a 2-0 victory at the Etihad.
The Reds stunned City in the opening minute of the match and Bruno Fernandes scored a penalty, then Luke Shaw doubled United's lead in the 50th minute and they managed to hold on to the victory.
Although City controlled most of the ball, they were underwhelming for the majority of the game - something we have not seen for a while.
Story of the game
Chaos is a great word to describe the opening minutes of this match and that chaos started in the first minute when Man United were awarded a penalty.
Anthony Martial picked up the ball after Marcus Rashford was dispossessed and he drove into the City area. Gabriel Jesus clipped United's number nine and Anthony Taylor pointed to the spot after just 36 seconds.
Fernandes kept his head and converted the penalty into the bottom left corner to score his 23rd goal of the season. Ederson managed to get a hand to the ball but could not keep the ball out.
The chaos continued and City looked shocked in the first ten minutes but it did not take long for the Citizens to take control of the game and probe for an equaliser.
Raheem Sterling was looking for a penalty when he drove into the box from the left but nothing was given. A minute later, Oleksandr Zinchenko stung Dean Henderson's gloves with a long-range strike and the United keeper parried it well.
Just before the half-time whistle, Jesus was inches away from connecting with Riyad Mahrez's low cross. However, he was unable to and Solskjaer's Reds went into the interval 1-0 up.
It was yet another strong start to the half in the second period, and just five minutes after the match resumed, United doubled their lead with a rare goal from the in-form Shaw.
Henderson distributed the ball to the left flank with a strong throw and Shaw was able to bypass Joao Cancelo with his first touch. He then drove into the final third and after a one-two with Rashford, he found himself inside of the City penalty area. He took a touch before calmly slotting past Ederson to give his side a two-goal lead.
The remainder of the second half involved a lot of defending for the away side, but they also managed to create chances on the break. Martial was through and found himself one-on-one against Ederson mid-way through the half, he could have finished City off, but his shot was straight at the goalkeeper.
It wasn't City's game, it just wouldn't work out for them in the final third. Phil Foden came off the bench and came close on 74 minutes when he dragged his shot wide. Then four minutes later, Sterling somehow missed a clear opportunity from a cross on the right.
The defending was brilliant from United, encapsulated by Mason Greenwood's brilliant tackle on Foden in his own area minutes after coming on for Rashford; who minutes earlier, ran the length of the pitch to stop a City attack.
It was a strong end to the match for United and they didn't look like conceding to the best team in the country. It ended 2-0 and it was not a flattering result, they deserved to win the game.
After all the media talk recently about Man United and their poor big-game record this season, this game was a statement from Solskjaer's team, who now move back into second place in the Premier League.
They carry on their impressive away record, 22 games without a loss away from Old Trafford - while they simultaneously end the record of their neighbours and they did it with a Fernandes penalty too, which makes it all the more sweeter.
It was a result that put United back on the right track to end their season strongly, both in the league and the cup competitions that they are in.
As for City, they will probably still go on to win this league title but United have disrupted their fine form as the pair prepare for the final ten matches of the season.