Novak Djokovic has confirmed his favourtism for the US tennis Open title after repelling former champion Andy Murray in an enthralling late night quarter final.

The world number one closed out a four sets triumph well after one in the morning New York time.

He says it's always a battle against Murray.

Djokovic says Murray is such a good returner who steps in and goes for every shot he has.

Djokovic will face Kei Nishikori in the semi finals.

Tomas Berdych is about to face Marin Cilic in the quarter finals with Roger Federer and Gael Monfils to play this afternoon.