Marcus Rashford inspired Manchester United to a derby-day comeback victory over Manchester City and spark a potential Premier League title charge.
The Red Devils ran out 2-1 winners on home turf after Citizens substitute Jack Grealish had opened the scoring in the second half. Erik ten Hag's soon men found their spirit to make it eight successive wins at Old Trafford, as Rashford - who'd looked set to come off at half-time with injury - continued his red-hot form after Bruno Fernandes equalised in controversial circumstances.
Pep Guardiola's side could now be eight points adrift of league leaders Arsenal by the end of the weekend, having lost for the second time in four days following an EFL Cup quarter-final defeat to Southampton. It was a momentous day for the red half of the city.
Here are six talking points from Old Trafford.
1. Ten Hag so Shaw
Ask Manchester United fans who their player of the season has been and many would reply by naming Lisandro Martinez. After a tough start to life in the Premier League, the £57million centre-back began to thrive in Erik ten Hag's side and became a World Cup winner in December with Argentina.
But since he's returned to Manchester, he's managed only one start - Tuesday's EFL Cup quarter-final win against Charlton Athletic. That's because Luke Shaw, who first deputised for Martinez in his post-World Cup absence, has excelled in a makeshift position and his form convinced Ten Hag to stick with him for this one and have him partner Raphael Varane - even up against Erling Haaland.
"The last couple of games, a lot of clean sheets, they [Varane and Shaw] played really well together," Ten Hag told MUTV pre-match. "Also, Licha Martinez returned from the World Cup and didn't have a lot of games. He played 90 minutes against Charlton, but we need big games."
2. Haaland's new role
When Erling Haaland chose to sign Manchester City over a host of other pleading European suitors in the summer, his mega-money transfer move begged question: how would he adapt to Pep Guardiola's system? For much of the season, however, it's more been a case of Guardiola adapting to Haaland.
Rarely acting as the kind of striker we've come to expect to lead the City assault throughout the past six years, the Norwegian powerhouse has instead skirted the offside line and played on the last man, scoring a whopping 27 goals as a result. Here, though, it was evident within the first 15 minutes that Haaland was trying something new.
Dropping deep in build-up and attempting to link play, the Golden Boot favourite looked more like former Citizens Sergio Aguero or Gabriel Jesus than his normal self. It gave Guardiola and co further dominance in possession but blunted their attack, as it took 23 minutes for them to register their first shot, That was through Haaland, of course.
3. Sort it Wout
For what feels like the first time since Haaland arrived in the Premier League, someone else is the most in-form player right now. That man is Marcus Rashford, scorer of seven goals in his previous six games and the Red Devils' talisman amid a resurgent run either side of the World Cup break.
Unfortunately for the England international, though, his favourite fixture - derby day - didn't start as planned. After squandering guilt-edged chances in the first half, Rashford dropped to the deck in pain clutching his hip. The Mancunian persevered for the final six minutes of the half but it appeared that Antony was set to take his place at half-time.
To everyone's surprise, however, it was Anthony Martial who made way at the break, having passed a late fitness test to start. The French striker had only played in spurts throughout the opening 45 minutes and clearly wasn't at full throttle, forcing Antony to take his place and lead a forward line desperately in need of reinforcements. Good thing new signing Wout Weghorst was watching on from he stands.
4. Jack the lad
Just as it seemed that Jack Grealish had established himself as a regular starter for City, the Birmingham-born ace found himself on the bench at Old Trafford in place of Phil Foden. That only lasted until the 57th minute, though, as Guardiola had seen enough and called on Grealish to make a difference.
Like a £100million player should go, the playmaker only took three minutes to make an impact and put the Citizens ahead of with a simple header after a trademark Kevin De Bruyne cutback. Capitalising on United's sluggish start to the second half, City flexed their muscles and broke through the Red Devils' defence, with De Bruyne shrugging off Casemiro and dinking a cross in towards Grealish.
The ex-Aston Villa captain had a simple tasking after evading Aaron Wan-Bissaka, nodding beyond David de Gea for what turned out to be visitors' only effort on target all afternoon. Grealish now has one goal and three assists in his last four league games, and he's starting to put up the kind of numbers many expected upon his arrival 18 months ago.
5. Red Devils' reprieve
What would an enthralling Premier League clash be without someone offside controversy? With little over 10 minutes of normal time remaining, United snuffed out an equaliser which will be debated all weekend long.
As Casemiro swept a ball through the City back line, Rashford looked certain to get on the end of it and be flagged offside. But the 25-year-old wisely let the ball go and allowed Bruno Fernandes to smash past Ederson and make it 1-1. The Citizens vehemently appealed but the current law means that Rashford didn't directly interfere, meaning the goal stood and Old Trafford shook with jubilation - and it was only going to get better for the home fans.
Have your say! Who'll finish higher this season - United or City? Give us your prediction in the comments section.
6. Red hot Rashford
Make that eight goals in seven games for Marcus Rashford MBE! Just as the Red Devils got back level terms, game-changing substitute Alejandro Garnacho decided to take the game to City and probe their creaking rearguard, as assisted Rashford for the winner after his first delivery was blocked.
A simple finish for the in-form Manc meant the game was all-of-a-sudden turned on its head, with Ten Hag storming down the touchline in celebration and the Citizens left dumbfounded.. There's now just one point separating the two Manchester sides in the table, and now United will fancy themselves for an unlikely title tilt.
