Chelsea boss Maurizio Sarri says they have the "best player in Europe" after Eden Hazard's hat-trick in victory over Cardiff City.

Hazard's treble and a Willian strike ensured that the hosts recovered from going behind to Sol Bamba's opener.

And Sarri said that Hazard has surprised him by just how good he is.

“I thought he [Hazard] was one of the best players in Europe, but now I change my mind that he is the best," said the Italian after the game.

To date, the 19 goals Hazard scored in all competitions in the 2014/15 season is the best he has managed in a single campaign, but his boss has a challenge for him.

“I think Hazard can improve more," he continued.

"I think that he can spend less energy than now at 50 or 60 metres to the opposition's goal.

"When we have the ball in our half and he touches the ball five or six times, it shows he spends a lot of energy and can have more energy in the last 25 metres.

“He can score 30 or 35 goals."