Former Genk chief Dirk Degraen says Napoli defender Kalidou Koulibaly should be playing for a "bigger club".

Degraen was RacingGenk's sporting director when Koulibaly left the Belgian champions for Napoli.

“The deal reached €10m with bonuses," he told Sky Sport Italia.

“It was a deal that took off with De Laurentiis. He was earning €1,500 a month.

“We met up yesterday and spent 45 minutes together for a drink. I think he's one of the best defenders in the world.

“It's a shame that he hasn't made the step-up to a big European club yet. I think it'll be difficult for anyone to buy him from De Laurentiis."