World number one Novak Djokovic continued his rich vein of form as he claimed a comfortable straight-set win over Ze Zhang of China to advance to the China Open quarterfinals on Thursday.
The Serbian defending champion clinched a 6-2, 6-1 victory over Zhang in a thrilling second round match that lasted for about an hour.
Djokovic will now lock horns with American John Isner, who has also made it to the quarterfinals by defeating John Millman 4-6, 7-6 (7-5), 6-4.
