Eliaquim Mangala has warned Manchester United new boy Anthony Martial that he faces a tall order to justify his £36m billing in his first season in England.

The 19-year-old striker became the world's most expensive teenager on deadline day after United signed him from AS Monaco in a deal that could potentially rise to £58m.

Mangala, who secured a £30m move to Manchester City last summer, struggled during his maiden season in the Premier League, and he has warned his France teammate to expect similar hardship.

"I do not think that the amount of the transfer would be a problem. Obviously no-one will look at him the same way anymore. Manchester United paid a lot of money for him," the defender told reporters in France.

"Let's see how he and people around him like the club or his family, deals with it, that's important. He must focus only on his football. It is what will be asked anyway. Everything else is inherent to the football world.

"Currently we can see some big amount within the transfer market. If we make a comparison with what we used to spend in the past, we realise it could go too far. In my opinion no-one is worth £50m, £80m or £100m. It is a part of the business of football. It is up to him to do well on the pitch. The first season can be tough; Premier League is a tough one. Totally different and very difficult. I hope he will be well received."

Arsenal and France legend Thierry Henry, with whom Martial has been compared, tipped the youngster to succeed.

Martial will wear the Red Devils' number nine shirt.