Ruud van Nistelrooy furious that Man Utd winner wasn't ruled offside

Harry Maguire scored controversial a late winner for Manchester United in Friday's FA Cup tie against Leicester. 

HARD TO TAKE: Leicester manager Ruud van Nistelrooy said his side were "not defeated in Fergie time" but "offside time". Pic: Nick Potts/PA Wire.

Ruud van Nistelrooy was furious after an "unacceptable" and "unthinkable" error saw Harry Maguire's offside winner stand as Leicester exited the FA Cup at his former club Manchester United.

The Dutchman started the season as one of Erik ten Hag's assistants and stepped up as interim manager, before being let go by Ruben Amorim and swiftly taking up the job as Foxes boss.