Former Liverpool defender Jamie Carragher has admitted that he is 'surprised' by Manchester United's decision to spend £36m on teenage striker Anthony Martial from Monaco.

The 19-year-old became the most expensive teenager in the world when he signed a four-year deal at Old Trafford on Tuesday.

According to FourFourTwo, when asked if he was surprised by the price, Carragher said: "I think so. He's the most expensive teenager in world football, so it's a big price. He comes with a lot of potential, which is expected at that age, just getting to the French squad as well.

"It's certainly a position they needed to strengthen, striker-wise, with the players that have moved on. He's a young player and when you talk about potential you're still not quite sure but for that price, he must be some player."

Martial has scored 11 goals in 52 Ligue 1 matches for Lyon and Monaco.