NEW YORK (AFP) - Second seed and 2012 champion Andy Murray crushed Bulgaria's Grigor Dimitrov 6-1, 6-2, 6-2 to reach his sixth US Open quarter-final on Monday.

The 29-year-old reigning Wimbledon and Olympic champion will face Japanese sixth seed Kei Nishikori for a place in the semi-finals.

Nishikori, the 2014 runner-up in New York, downed 37-year-old Ivo Karlovic 6-3, 6-4, 7-6 (7-4).