Van der Vaart urges Hamburg starlet Son to resist Liverpool: I know it's tough!
Former Tottenham star Van der Vaart knows Son is a top January target for Reds boss Brendan Rodgers.
"He must stay here," Van der Vaart told BILD. "Of course it is tempting when Liverpool approaches you and offers twenty million.
"Yet here he has confidence, he plays regularly and can get better. He is for us a very important player."