Success always comes at a price and Manchester United are likely to have to pay it sooner rather than later following Anthony Martial’s performance on Saturday.

The Frenchman arrived at Old Trafford from AS Monaco for £36m during the summer of 2015 with a clause in his contract that stated United would have to pay an additional €10m (£8.52m) should he reach 25 competitive goals for Jose Mourinho’s side.

Saturday was goal number 24 as Martial, along with an earlier finish from the sublime Juan Mata, saw Walter Mazzarri’s side swept away by a United performance that was so un-Mourinho like it almost defied belief. Forget parking the bus, this was revving the Ferrari.

Martial’s all-round showing – he plagued Watford relentlessly until his 80th-minute substitution - was the kind of effort that justified the money United spent on him but it was also a stark reminder of how much more the 21-year-old can give when body and mind are in sync.

Reports in December that his agent, Philippe Lamboley, was trying to orchestrate Martial’s Old Trafford exit clearly unsettled him and Mourinho has repeatedly spoken about how he is demanding more and more from Martial, determined to extract every ounce of his talent.