Novak Djokovic set up a mouthwatering Indian Wells semi-final showdown with nine-time French Open champion Rafael Nadal, who the world number one Serb considers his biggest rival on the ATP Tour. Both Nadal and Djokovic eased through their Indian Wells quarter-final contests in straight sets on Friday and will now square off in a match worthy of a title clash. "It is going to be a game of cat and mouse," Djokovic said. "I enjoy the rivalry against Rafa. It is probably the most exciting rivalry I have had in my career." World number five Nadal survived an early assault to defeat Japan's Kei Nishikori 6-4, 6-3 in the joint ATP and WTA Tour hardcourt tournament in the California desert. The Nadal-Nishikori match kicked off a star-studded pair of Indian Wells quarter-finals on Friday featuring four of the world's top 10 players.