MASON, Ohio (AP):

Top-ranked Roger Federer had another out-of-character defeat on Thursday, a 7-6 (8), 4-6, 7-6 (7) loss to Ivo Karlovic that left the Croat exulting on his back and opened the way for Rafael Nadal to take over the world No. 1 spot by winning the Cincinnati Masters.

Nadal stayed on course for the seismic shift by beating German Tommy Haas 6-4, 7-6 (0) later Thursday, reaching the quarter-finals with his 31st consecutive win. Three more wins and the top spot in the world rankings belongs to him.

Since his epic five-set loss to Nadal at Wimbledon, Federer has lost in the second round in Toronto and failed to make the quarter-finals at Cincinnati, where he won the title last year.