Tottenham boss Ange Postecoglou says Heung-min Son's fitness has been key to his form this season.

Postecoglou says Son's injury problems held him back last term.

"In terms of Sonny, it's fair to say, and he's said it himself, I don't think he was 100 per cent fit last year, but that's his nature, if asked to play, he will play and do his utmost," he said.

"I think that probably affected his form more than anything else. Last year was a bit of a unique year for a lot of players because of the World Cup. I don't think it was a normal year in many respects for top players.

“The quality Sonny has, there is no doubt… I don't think I've done anything dramatic to him, I think he just feels better. He's had a good pre-season and loves playing for this football club. I think the way we're playing really suits him for where he's at in his career. I'm sure there is more to come."