Mikel Arteta has said Ruben Amorim has already put his "fingerprints" on Manchester United but warned of the unpredictability of management as he tries to restore the club to former glories.

Arsenal manager Mikel Arteta has warned Manchester United counterpart Ruben Amorim of the "unpredictable" nature of life at the helm of one of England's top clubs as the pair prepare to do battle on Wednesday.

Amorim has spoken of his admiration for Arteta and while he can take some learnings from the Arsenal boss, there’s even more for the Portuguese to do at Old Trafford