The Belgian hasn't put a foot wrong since his arrival from Ajax last summer.
"You probably wouldn't expect me to say anything else, but Jan's been nothing short of fantastic, an unbelievable player," Parker told the Spurs website.
"He shows great composure on the ball, works hard, is an athlete and you've seen the goals he's scored as well.
"He's been massive for us this season and you can only see him getting stronger and stronger.
"Technically, he's a very gifted footballer. He's like a Rolls Royce, he glides around the pitch so effortlessly, he can step out with the ball and he's nicked a few goals as well. That's invaluable."