Leeds United conjured up a classic of a game to win at Manchester United for the first time in the league since 1981.
With an hour gone, it really should have been a gentle procession to victory.
The Whites were two Noah Okafor goals up when Lisandro Martinez was sent off for pulling Dominic Calvert-Lewin's pony tail of all things.
Within no time Leeds were playing ole football lapped up by the away end.
Yet a team who threw away a two-goal lead at West Ham United eight days earlier very nearly did so again.
All's well that ends well, perhaps, but the Whites made a dog's dinner of a big win for them.
The 2-1 success took them to 36 Premier League points and with three home games left, they should get to safety. But then they should have cruised to victory on Monday night.
Nothing is ever simple with a football club who really should carry a health warning rather than a sponsor's logo on their shirts.
DOUBLING UP: Noah Okafor celebrates his and Leeds United's second goal (Image: Carl Recine/Getty Images)placeholder image
DOUBLING UP: Noah Okafor celebrates his and Leeds United's second goal (Image: Carl Recine/Getty Images)
This game was like going out for one quiet drink and downing far too many Red Bulls.
Hearing Old Trafford boo their players off at half-time was music to the ears of the visiting side and the sound of a job very well done.
With Harry Maguire suspended, it was no surprise Leeds put lots of crosses in, but they caused as much bother with low ones as lofted ones.
Add in ferocious pressing, and they led 2-0 at the break, although it could have been more as they got their reward for a positive selection featuring wing-backs, not full-backs, and Ao Tanaka's midfield guile.
HAVE A LOOK: Paul Tierney reviews Lisandro Martinez's challenge with Dominic Calvert-Lewin before sending the Argentinian off for hair pulling (Image: Paul ELLIS / AFP via Getty Images)placeholder image
HAVE A LOOK: Paul Tierney reviews Lisandro Martinez's challenge with Dominic Calvert-Lewin before sending the Argentinian off for hair pulling (Image: Paul ELLIS / AFP via Getty Images)
It took just two minutes for Senne Lemmens to be called into action, Calvert-Lewin sliding on to a Gabriel Gudmundsson cross.
They were ahead inside five minutes, this time the cross coming in from the right, and Okafor getting on the end of Jayden Bogle's delivery. Lenny Yoro nodded the ball away from Calvert-Lewin but to the Swiss, who finished calmly and accurately.
Jaka Bijol headed wide at a corner when another Bogle cross was deflected behind in the 19th minute.
When Bruno Fernandes went down claiming a foul, Paul Tierney decided to do the refereeing himself and as the Portuguese stropped on the floor, James Justin stepped up from centre-back to deliver the ball. Although Yoro cut it out, Ethan Ampadu's hungry pressing won it. The ball bounced around for a long time before Okafor volleyed inside the far post to send the away fans into delirium after 29 minutes.
MADE IT: Gabriel Gudmundsson (far right) celebrates his assist for the opener (Image: Carl Recine/Getty Images)placeholder image
MADE IT: Gabriel Gudmundsson (far right) celebrates his assist for the opener (Image: Carl Recine/Getty Images)
A stretching Calvert-Lewin could not control his header from another Bogle ball but Leeds came very close to a third shortly before half-time.
Lammens' pass put Yoro in trouble and Leeds won it back, Ao Tanaka taking it around the goalkeeper. A slightly heavy touch allowed Martinez to slide in and deny him a tap-in.
At the other end, straight balls down the middle looked like being Leeds' undoing, but the Red Devils were not clinical enough to make the most of them.
Amad Diallo was the chief threat, getting between Gudmundsson and Bijol in the 12th minute, only for Karl Darlow to get down and save.
When Diallo picked Benjamin Sesko out, the shot was weak with Bijol closing him down. Diallo curled an effort just wide.
Matheus Cunha's shot from distance swung away from Darlow's outstretched hand like Waqar Younis had let it go, but cleared the crossbar.
DENIED: Lisandro Martinez slides in to stop Ao Tanaka scoring Leeds United's third (Image: Carl Recine/Getty Images)placeholder image
DENIED: Lisandro Martinez slides in to stop Ao Tanaka scoring Leeds United's third (Image: Carl Recine/Getty Images)
That Leeds made a game of it was not the greatest shock, but doing it against 10 men was.
Justin had to head off the line when Sesko nutmegged Bijol in the 48th minute and Darlow's save looped the ball goalwards, but the game should have been over when Martinez was sent off in the 56th.
From a distance it just looked fairly standard tussling between two physical players but Tierney was alerted to some hair pulling by video assistant referee John Brooks.
But when Michael Carrick called for forward Bryan Mbuemo as one of his changes, the Stretford End erupted and before he even got on, their side had pulled a goal back.
Casemiro popped up in space at the back post to head in a Fernandes delivery with 21 minutes to play, and from Leeds playing ole football a few minutes earlier, a manic basketball game broke out.
Lammens saved on his line from a Calvert-Lewin header, Bijol needed to make a big tackle on Mbuemo, Cunha volleyed wide, Darlow saved from Sesko, then Calvert-Lewin headed off the line from the corner. Ampadu hit a shot into Manuel Ugarte.
The game was frantic and breathless when from a Leeds perspective, it really should not have been.
But they got there in the end.
Manchester United: Lammens; Mazraoui (Dalot 70), Yoro, Martínez, Shaw; Casemiro, Ugarte; Diallo, (Mbeumo 70) Fernandes, Cunha; Sesko.
Unused substitutes: Bayındır, Mount, Zirkzee, Malacia, Heaven, T Fletcher, Lacey.
Leeds United: Darlow; Justin, Bijol, Struijk; Bogle, Ampadu, Tanaka (Gruev 69), Gudmundsson; Aaronson (Longstaff 86), Okafor (Gnonto 69); Calvert-Lewin.
Unused substitutes: Perri, Piroe, Nmecha, Bornauw, Byram, Buonanotte.
Referee: P Tierney (Wigan).