Manchester United came from 1-0 down to claim a stunning 2-1 win over rivals Manchester City at the Etihad.
In a shock turn of events, City found themselves 1-0 up on 87 minutes having opened the scoring through Josko Gvardiol's first half header and looked to be edging their way to three points, which would have been their second win in 11 games.
However, United's Amad Diallo won a penalty after being tackled clumsily inside the City box by Matheus Nunes, with Bruno Fernandes converting the spot-kick to make it 1-1. And then, somehow, United took the lead minutes later through Diallo.
A long ball in behind the City defence from Lisandro Martinez found Diallo racing through on goal with Ederson rushing out. The Ivorian forward dinked the Brazilian, before finishing from a tight angle to send the United fans inside the Etihad wild.
And here are five things United boss Ruben Amorim learned...
Manchester Miracle
Amad Diallo
Amad Diallo netted a stunning late winner to shock the Etihad (Image: Getty Images)
Manchester United produced a miracle to beat Manchester City at the Etihad thanks to late goals from Amad Diallo and Bruno Fernandes. It was a stunning turnaround, one which United deserve masses of credit for.
Prior to the Manchester derby, Pep Guardiola's side had won just one of their last 10 games in all competitions. They were there for the taking, failed to create anything from open play and looked low on confidence.
But despite being 1-0 down, United kept plugging away. They stayed in the game, and took their chances late on to claim a famous win at the Etihad. It will take time for him to turn things around at Old Trafford but there are signs Amorim is doing a decent job so far. He needs to be backed in January and the summer.
Amad Diallo stars
Amad Diallo
Amad Diallo was the star of the show for Manchester United (Image: PA)
Amad Diallo was everywhere against United and served as the catalyst for their stunning comeback.. He nearly put them ahead in the first half but blazed his effort wide. In the second half, he had a header saved by Ederson.
He won the penalty to get United back into the game, and produced a stunning effort to win it for Amorim's side. What a player he looks and Amorim deserves credit for giving him the minutes Erik ten Hag would not.
From zero to hero
Skipper Fernandes went from zero to hero. The United captain missed their best chance of the game when he opted to dink Ederson in the second half, but converted from the spot on 87 minutes after Matheus Nunes silly foul on Amad Diallo.
It was a pressure penalty from the United captain, one which levelled proceedings at the Etihad and served as the platform to help them go on to win the game through Amad Diallo.
More set-piece woes
Once again, United were undone by a set-piece. In their recent matches, they conceded twice to Arsenal from a set-piece, and also against Nottingham Forest too last weekend.
While the ball for City's opener from Kevin De Bruyne did take a deflection off Diallo, it was still poor from Diogo Dalot and Rasmus Hojland, who failed to deal with the cross.
Amorim needed to fix United's issues when it comes to defending set-pieces. Only Wolves (nine) have conceded more than United's eight this season, a number which is way too high for a team wanting to compete for at the top end of the Premier League table.
Attackers needed
Despite the masses of money spent on attackers, United really could do with some more. Hojlund at times looks a threat but there's no consistent service for the Danish striker. Mason Mount, who was selected to start in behind Hojlund alongside Diallo, also went off injured, forcing Amorim to bring on Kobbie Mainoo and move Bruno Fernandes further forward.
Put simply, United need more quality in the final third. Their first shot on target came just after the hour mark through Diallo, whose glancing header was saved by Ederson.
While they produced a spectacular comeback thanks to goals from Diallo and Fernandes, they could still do with some more attacking threat.
The only way they can improve their attacking woes is by either Amorim doing an incredible job coaching up the current squad, or by bringing in some new attackers who fit the 3-4-3 system. They could be set to give up on Rashford, who was not named in the match day squad which would free up some money in January if they can sell him.