Manchester United’s 1-0 defeat to Portsmouth in the quarter-final of the 2008 FA Cup means the win that came before it is very often forgotten about.

The Red Devils booked their place in the last eight with a thumping 4-0 win over Arsenal at Old Trafford.

Wayne Rooney produced a man of the match display, his header in the 16th minute paving the way for a resounding victory.

Two goals from Darren Fletcher and Nani’s effort completed the win.

The latter years of Rooney’s Man United career were pretty miserable but he was at his very best against Arsenal.

Indeed, Arsene Wenger described his performance as “fantastic”, while predicting that Rooney, who played as a lone striker, wouldn’t continue to play up front on his own.

"I wouldn't say in the longer term that this is his best position because he's a player who likes to get the ball, but in a one-off game he can do it," Wenger said, per The Guardian.

"I don't think in the long term he will be a lone striker.

"Against us I thought Rooney was fantastic. He was sharp, mobile, quick, aggressive, even good in the air. He did everything."

Rooney mocked Arsenal

That included taking the mickey out of Arsenal.

Rooney was flagged for offside on the hour mark and refused to give the ball back straight away.

Instead, he decided to show off his ball retention skills, much to the frustration of William Gallas and Gilberto Silva.

Rooney was booked but the Man United supporters didn’t care. Watch the video below.

Back when Rooney was at his brilliant best. Check out the highlights from that 4-0 win.

Man United lost to Portsmouth in the next round

Man United’s joy turned to despair in the following round when they were upset by Portsmouth.

Sulley Muntari scored the only goal in a game that saw Rio Ferdinand play in goal and Sir Alex Ferguson berate referee Martin Atkinson after the defeat.

“The referee's performance today was unacceptable, but he'll be doing it again next week,” Ferguson said, per The Guardian.

The retired manager was fuming that Cristiano Ronaldo wasn’t awarded a penalty.

“Don't even ask me why Ronaldo didn't get a penalty, I cannot explain that decision and I don't think anybody could,” Fergie added.

Rooney showing players up, Ferguson moaning at referees. Those were the days.

What was Rooney's funniest moment for Man United? Let us know in the comments section below!