United’s luck certainly wasn’t in at the Amex.

Manchester United had their second goal against Brighton ruled out after an incredible offside offence was spotted.

United thought they had taken a 2-1 lead on 70 minutes, when Alejandro Garnacho arrived at the back post to tap in Bruno Fernandes’ cross.

The Argentinian, who came off the bench for the second time in a week, claimed the goal and went over to celebrate, with his team-mates following him.

But the ball actually took a touch off fellow substitute Joshua Zirkzee – with the question being whether the Dutchman actually touched it before it went over the line.

Slow-motion replays showed that Zirkzee’s knee was not over the line by the barest of margins.

And to make things worse, he was marginally ahead of Garnacho when he took the shot – meaning VAR had to adjudge him to be offside and disallow the goal.

The Premier League clarified the decision on their Match Centre Twitter account, writing: “Zirkzee’s goal was awarded on-field.

“The VAR checked for a potential offside against Zirkzee and recommended that the goal was disallowed. [The referee] restarted play with a Brighton free-kick.”

Erik ten Hag’s side had earlier gone behind in the first half through former United striker Danny Welbeck, who scored his 100th career goal.

United then equalised through Amad Diallo, making his first Premier League start of the season.

But it was to be late heartbreak for Ten Hag and United, as Joao Pedro was left unmarked in the penalty area from a Brighton cross and he headed the ball into the bottom left corner beyond Andre Onana.

The visitors had no time to get back into the contest at the Amex Stadium, meaning United were consigned to their first league defeat in the Premier League this season.