Manchester United legend Rio Ferdinand says Arsenal must cough up to keep hold of Alexis Sanchez.

Sanchez has been in superb form since being deployed up front and hat-trick produced heroics as the Gunners secured a 5-1 victory over London rivals West Ham this evening.

"If he comes in and says 'I want to be your top paid player' then they can't argue," Ferdinand told BT Sport.

"He's had the opportunity to go to a team that was winning [Barcelona] and it didn't quite happen for him.

Here he's the main, the talisman, the kingpin and he might want that for his ego."