Wawrinka, Nishikori through to Japan Open semis

Switzerland's Stan Wawrinka reacts after defeating Austin Krajicek of the U.S. during their men's singles tennis match at the Japan Open championships in Tokyo October 9, 2015. REUTERS/Thomas Peter

TOKYO (Reuters) - French Open champion Stan Wawrinka sailed into the semi-finals of the Japan Open on Friday with a 6-3 6-4 win over American Austin Krajicek. Wawrinka, who has already won three titles this year including his second grand slam in Paris, needed just 50 minutes to defeat Krajicek . The Swiss will play Luxembourg's Gilles Muller on Saturday after he upset French third seed Gilles Simon 6-3 6-4 in the quarter-finals. Kei Nishikori fought back to beat Marin Cilic 3-6 7-5 6-3 to record his second successive win against the player who beat him in last year's U.S. Open final. Nishikori, who won his home tournament in 2012 and 2014, set up a showdown with Frenchman Benoit Paire for a place in Sunday's final. Paire also from behind to defeat Australia's Nick Kyrgios 3-6 6-4 6-1. (Writing by Julian Linden in Singapore, editing by Pritha Sarkar)