Former Celtic coach John Collins says Liverpool defender Virgil van Dijk can be the best in the world.

Collins was with Celtic when they sold Van Dijk to Southampton.

"Southampton did very smart things, he proved me right, he plays like a Rolls Royce at top level week after week," said Collins.

Collins was asked whether Van Dijk is the best central defender in the world.

"Is he better than Gerard Piqué ? Yes, he is faster and better, he is as good as Sergio Ramos, and he will be better than Ramos."