Nishioka withdrew because of illness, sending David Goffin into the semifinals.
Nishikori lost an all-Japanese clash with Yoshihito
Nishioka, who defeated a man he calls his hero 7-6 (2) 6-4 for the biggest win of his career.
Australian Nick Kyrgios blasted 15 aces to blow past Japan's Yoshihito
Nishioka 6-2 7-5 on Thursday and reach the quarterfinals at the Citi Open in Washington, D.C.
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On the first day last year, Federer lost only eight games in easing past Dusan Lajovic, while the man he beat in the 2017 final, Marin Cilic, enjoyed a similarly smooth passage against Yoshihito
"I feel as if I contributed to his victory," he joked.Fourth seed Kevin Anderson, runner-up to Djokovic in 2018, eased into the second round beating Pierre-Hugues Herbert of France 6-3, 6-4, 6-2.Anderson will now play Serbia's Janko Tipsarevic who registered his first win at the tournament in seven years when he defeated Japan's Yoshihito
Nishioka 6-4, 6-7 (2/7), 6-2, 5-7, 6-2.In the women's event, third seed Karolina Pliskova made it through, beating China's Zhu Lin 6-2, 7-6 (7/4).
Next up for the giant Argentine is a clash against Japan's Yoshihito
THERE were seas of blue in the early markets for the BNP Paribas Open fourth-round matches of Dominic Thiem, Jan-Lennard Struff and Yoshihito
Nishioka, but Miomir Kecmanovic is capable of troubling the Japanese player if fit and well.
The Croatian veteran will face Austrian seventh seed Dominic Thiem, who beat France's Gilles Simon 6-3, 6-1.Lucky loser Miomir Kecmanovic of Serbia continued to make the most of his unexpected opportunity, beating fellow Serbian Laslo Djere, the 30th seed, 6-2, 7-6 (7/3).The 19-year-old will take on Japan's Yoshihito
Nishioka, who rallied from a set down to beat 18-year-old Canadian Felix Auger-Aliassime 6-7 (2/7), 6-4, 7-6 (7/5).
Fellow Briton and world number 64 Cameron Norrie also progressed in Acapulco, holding his nerve to beat Japan's Yoshihito
Nishioka 6-2 2-6 6-2.
TENNIS: Cameron Norrie beat Japan's Yoshihito
Nishioka 6-2 2-6 6-2 to set up a Mexican Open secondround clash with No.4 seed Diego Schwartzman.