Chelsea ace Diego Costa has been impressed by Monaco superkid Kylian Mbappe.

The teen has been linked with Real Madrid and Manchester United in recent days.

"If he continues to progress at this rate, he will be a phenomenon," said Costa.

"He is a killer in front of goal, besides he has a very good dribble. I hope he continues down this road."

It broke today that Monaco are demanding £130 million to sell.