Roger Federer tightened his grip on the world No 1 ranking after a crushing 6-0, 7-6 (7) defeat of Novak Djokovic to win a sixth title this season at the Cincinnati Masters.

The Swiss will take a healthy points lead of nearly 900 into the US Open, where No 2 Djokovic is defending the title, starting on Aug 27.

ATP calculations show that the 31-year-old Federer will maintain the top spot through the end of the season's last Grand Slam.