Manchester United face having to pay AS Monaco a bonus thanks to Anthony Martial's goals record.

His brace, along with two from Zlatan Ibrahimovic, fired Manchester United to a 4-1 victory over the Hammers and into the last four of the EFL Cup. United splashed out £36m last year to bring the 20-year-old to Old Trafford.

And as part of that deal, United will have to pay a further £8.4m when Martial reaches 25 goals for the club.

His double on Wednesday took him to 21 goals as a United player.