Manchester United made Anthony Martial the most expensive teenager in the world when they paid AS Monaco £36 million - potentially rising to £58m - for him in 2015.History suggests that those who are bought for huge fees at such a young age don’t always develop into world beaters - Man United paid more than £30m for Luke Shaw three years ago - and that applies to Martial.It’s been an up and down ride for the Frenchman at Old Trafford. Jose Mourinho dropped him from his starting line-up last season but it would appear that he’s over a troubled campaign in which off-the-field drama appeared to impact his form.Martial has produced a string of impressive moments to start the 2017-18 season and chipped in with four goals.Of course, Mourinho has Louis van Gaal to thank for signing Martial two years ago.Van Gaal managed to beat Arsenal to the forward’s signing but it wasn’t much of a battle; the Gunners were never going to pay Monaco such a hefty fee.

What Wenger said when Man United sign Martial

Reflecting on Man United’s capture of Martial, Arsene Wenger said it was an “absolutely huge investment” to make on a young player.

“What happened last night [Tuesday] with Monaco, who sold Martial to Manchester United for 80million Euros, I’ve heard,” Wenger told beIN Sports, via the Daily Mail.

“Martial scored 11 goals in the French championship - that sums it up well. Martial is a huge talent - he’s 19 years old.

“The investment is absolutely huge as well. It shows you that there’s not many players in the world who can strengthen these teams.

“The problem at the moment is finding the players that guarantees you are a better team after, and that example last night shows you very well.”

Wenger just won't compete for the best

Wenger’s attitude towards spending money has remained the same throughout his lengthy spell at the club.

It’s why you will hear of Arsenal’s interest in players like Martial and Kylian Mbappe - young, French stars who could be convinced to work with Wenger - but never announcements of their arrival.

Martial hasn’t fulfilled his potential just yet but at least Man United are giving him the best opportunity to do so.

How much better can Anthony Martial become? Let us know in the comments section below!