WASHINGTON — Playing nearly mistake-free, Kei Nishikori moved into his 11th ATP quarterfinal of the season by beating 16th-seeded Leonardo Mayer of Argentina 6-4, 6-4 at the Citi Open on Thursday.
The second-seeded Nishikori made it to the final eight at the hard-court tuneup for the U.S. Open for the second consecutive year. Later in 2014, he would go on to become the first man from Japan to reach a Grand Slam singles final, getting that far at Flushing Meadows.
Against Mayer, Nishikori made only seven unforced errors, half as many winners as he produced in the 1½-hour victory.