Marcus Rashford scored the winner as Manchester United came from behind to beat Manchester City 2-1 and go third in the Premier League in a thrilling finale at Old Trafford on Saturday.
Both United goals came in the final 12 minutes as Erik ten Hag's side moved to within one point of their local rivals in the table after inflicting a damaging blow to City's hopes of retaining the title.
Pep Guardiola's men looked to be heading to victory when Jack Grealish came off the bench to head the visitors into the lead.
But Bruno Fernandes' controversial equaliser turned the game and four minutes later Rashford netted for the ninth consecutive match at Old Trafford.
City could now fall eight points off the top of the table should Arsenal beat Tottenham in the north London derby on Sunday.
The victory for United was sweet revenge after being destroyed 6-3 when the sides met in October.
The scoreline even flattered United at the Etihad thanks to two late goals from Anthony Martial.
However, Ten Hag's men have now lost just once in 19 games since in a stunning turnaround in the Dutch coach's first season in charge.
The introduction of Casemiro has transformed United's midfield since the last Manchester derby and Ten Hag's decision to play Fred alongside his Brazilian international teammate cut City's supply line to Erling Haaland.
Marcus Rashford becomes the first United player to score in nine #PL matches in a row at Old Trafford since Dennis Viollet in 1959 ??#MUNMCI pic.twitter.com/4StlfpzYVI
— SuperSport Football ?? (@SSFootball) January 14, 2023
United's turnaround is reflected in Rashford's revival. The England international has now scored 16 times this season.
RASHFORD THREATENS
Rashford's pace in behind was the biggest threat posed by either side in the first half and he should have done better after rounding Ederson than allowing Kyle Walker to comfortably clear off the line.
Another Rashford burst then took him beyond Rodri, but again the finish was lacking as Ederson hurried off his line to smother.
United's new loan signing Wout Weghorst was watching on from the stands and Martial's lacklustre performance before being replaced at halftime by Antony underlined Ten Hag's need for more forward options.
By contrast, City are blessed with an abundance of talent in the final third and Guardiola's ability to make game-changing substitutions looked to have swung the game in their favour.
Grealish had only been on the field three minutes before netting the biggest goal of his City career to date as he nodded in Kevin De Bruyne's cross on the hour mark.
But City have struggled this season to match the consistency that has won them four Premier League titles in the past five years and were undone by a hugely controversial equaliser.
Rashford was clearly offside as he raced towards Casemiro's pass, but crucially did not touch the ball and left it for Fernandes to sweep home.
The assistant referee initially flagged for offside and City were livid at the decision to allow the goal to stand.
City were still rocking when they conceded again as Alejandro Garnacho sprinted down the left and crossed for Rashford to prod home from close range.
There was still time for City to feel further aggrieved at referee Stuart Attwell as Haaland saw a penalty appeal waved away.
But the champions now have a huge job on their hands if they are to maintain their dominance of English football in the Guardiola era.