Ruud van Nistelrooy knows all about 'Fergie time' - the term used by some football fans to describe late goals scored by Manchester United when Sir Alex Ferguson was manager.

But, after his Leicester side were knocked out of the FA Cup by a controversial stoppage-time Harry Maguire header on his Old Trafford return on Friday, the Dutchman had a new way to describe such drama.

"We are not defeated in Fergie time, we are defeated in offside time," the former Manchester United striker told ITV after his side were beaten in round four.

His frustration was that, with the scores level at 1-1 and the game in the third and final minute of injury-time and heading for 30 minutes of extra time, Maguire headed the winner, despite appearing to be offside when Bruno Fernandes sent a free-kick towards the back post.

But with no video assistant referee (VAR) at this stage of the FA Cup, it was down to the decision of the officials, who felt there was nothing wrong with the goal.

Having had a bit more time to digest the outcome when he faced the media around an hour after full-time, Van Nistelrooy was no calmer about the situation.

"We are gutted," he said.

"When you prepare for the whole week for this game and reacting after the Everton loss and put in a performance like that but it is decided on a clear and obvious mistake, that is unacceptable and unthinkable at this level.

"We have nothing else to do but pick ourselves up. It is not what the team deserved."

Ruud van Nistelrooy said Harry Maguire, the furthest Manchester United player from the ball at the far side of the penalty area in the above image, was "half a metre" offside.Having had time to analyse replays of the goal, VAR would most likely have overturned the on-pitch decision.

However, the Football Association announced in mid-December that the technology would not be used in the FA Cup until the fifth round.