Manchester United upped their bid for Anthony Martial from £21.6m to £57.6m as Tuesday's transfer deadline approached, according to Monaco vice president Vadim Vasilyev.

The Red Devils made Martial, 19, the most expensive teenage footballer in history when they sealed his big-money move on the last day of the summer transfer window.

The final sum does include bonuses - one of which, reportedly, is £7m if he scores 25 goals across his four-year contract - but Vasilyev says it is the kind of sum that is usually reserved for the likes of Barcelona forwards Luis Suarez and Neymar.

"It's true that the price for Martial is £57.6m but take into account this sum includes bonuses which are very realistic," he told The Sun.

"Initially Martial was not for sale, it was absolutely not planned. Since last week United started to make offers which we declined several times – £21.6m, £28.8m, £36m, even £50.4m with bonuses.

"On Sunday the player got such an offer that he couldn't have declined. He asked us to find a solution and on Monday morning Manchester United made an offer to Monaco which the club couldn't refuse.

"It's absolutely unique. It's the price of Luis Suarez or Neymar – the best players in the world.

"Right now English football is on a different financial level and if Manchester United decides to buy somebody, it's very hard to stop them."