The turning point came early in the second half when Martinez was sent off by referee Paul Tierney following a VAR review. The Argentine defender was judged to have pulled the hair of Dominic Calvert-Lewin after an aerial duel.

Tierney confirmed: "After review, Manchester United number six is guilty of pulling his hair - violent conduct. Final decision is red card."

Carrick, however, strongly disagreed. "It's not a pull, it's not aggressive," he told Sky Sports. "He touches it and gets sent off. For me, it's a shocking decision. One of the worst I've seen."

The United boss also pointed to an earlier incident in the build-up to Leeds' opener, claiming his side were denied a foul. "Leny Yoro takes a forearm in the back of the head and nothing is given. That was a big moment," he said.

Leeds made their fast start count. Noah Okafor struck twice in the first half, first finishing from close range after a cross from Jayden Bogle, before adding a second with a deflected effort. United struggled for rhythm but nearly responded through Benjamin Sesko, only to be denied on the line.

After Martinez's dismissal, United rallied. Casemiro pulled one back with a header from a Bruno Fernandes delivery, setting up a tense finish. Fernandes later admitted his frustration: "If I speak about the referee, I get in trouble. It's better I don't say anything."

Leeds had chances to seal it, with Calvert-Lewin missing a clear header, but they held firm. Their manager Daniel Farke praised his side's composure. "Tired, relieved, proud," he said. "We were fantastic in the first half and deserved more. We are on a good path."

The win lifted Leeds further clear of the relegation zone and secured a rare league victory at Old Trafford, their first in decades. Meanwhile, United stayed third in the table but now faced a major setback, with Martinez suspended for upcoming clashes against Chelsea, Brentford and Liverpool.

Chelsea's Wesley Fofana accepts apology from Enzo Fernandez over offensive video