Leeds stunned Manchester United with their first league win at Old Trafford since 1981 as they took a giant stride towards safety on a bad night for Michael Carrick's side.

Minority shareholder Sir Jim Ratcliffe sat stony-faced in the directors' box as Manchester United produced a chronic first-half display.

They improved after half-time but only after Argentina defender Lisandro Martinez, returning after two months out through injury, was sent off for pulling Dominic Calvert-Lewin's hair.

Noah Okafor put the visitors in front with a clinical first-time effort after just five minutes and had Leeds two ahead by half-time with a shot that flicked off Leny Yoro and into the corner.

Martinez's dismissal following a video assistant referee (VAR) intervention seemed to spark the hosts and Casemiro pulled one back for Manchester United as Bruno Fernandes produced his 17th assist of the season - three short of the Premier League record for a single campaign.

A man down, they kept pushing for an equaliser and Benjamin Sesko was denied twice in a minute thanks to a save from goalkeeper Karl Darlow and Calvert-Lewin's goalline clearance.

The leveller eluded them though as they suffered the first home defeat of Carrick's time in charge.

It means they go to Chelsea on Saturday, a game Harry Maguire might yet miss through suspension, knowing defeat will leave them four points ahead of Liam Rosenior's erratic team with five games remaining.

Leeds, meanwhile, host bottom side Wolves at Elland Road, before any of their relegation rivals are in action again, knowing if they win they will be nine points clear of the drop zone.

It had been often mentioned in the build-up that Manchester United had a 24-day gap in games since their 2-2 draw at Bournemouth.

That might have been a legitimate explanation for their sluggishness in an opening period when they were totally outplayed by a Leeds side that had been sharpened by their FA Cup win at West Ham eight days earlier.

It resulted in Carrick striding to the dressing room with the sound of boos ringing in his ears as the home fans made clear their thoughts of what they had just witnessed.

They did improve in the second half but the result is almost secondary to the consequences of Martinez's ridiculous red card.

The Argentina defender will miss three games - Chelsea away and home games against Brentford and Liverpool.

Every one of those fixtures represents a serious threat to Manchester United's Champions League hopes.

But the Chelsea trip may have an added issue. Maguire should find out in the next 48 hours whether the Football Association (FA) charge into his reaction to being sent off at Bournemouth last month means he is suspended for another game.

If it does, the likelihood is 19-year-old Ayden Heaven will be partnering 20-year-old Yoro in central defence.

Carrick has cruised through his first few months at the helm. Now the problems are mounting up.

The joy of the Leeds fans as they remained in the stadium and sang their songs long after the final whistle and their jubilant team had left the pitch underlined just what this win - against this particular opponent, on this particular ground, after so long - meant.

There were 3,000 Leeds supporters inside Old Trafford, but legend will claim there were far more.

But for Daniel Farke and his players, beating Manchester United is worth something far more significant.

Premier League survival has come down to a battle between four clubs, with one of them destined to join Wolves and Burnley, who are surely Championship-bound.

Had Calvert-Lewin taken the two gilt-edged chances that came his way either side of Okafor's double, the late scares would have been avoided, so too if Martinez had not denied Ao Tanaka with an amazing goalline tackle to prevent Leeds going three up by half-time.

Regardless, in their mini-battle, Leeds are now six points clear of Tottenham, who occupy the third relegation spot. If Leeds beat Wolves at Elland Road before any of their rivals play this weekend, the gap will be nine.

That is all Farke will care about. The fans will carry on singing.

Manchester United are next in action in the Premier League against Chelsea at Stamford Bridge on Saturday, 18 April (20:00 BST), after Leeds host Wolves on the same day (15:00).