NEW YORK, United States (AP) — Naomi Osaka became the first Japanese woman to reach the quarter-finals of a Grand Slam in 14 years, edging Aryna Sabalenka 6-3, 2-6, 6-4 in a match-up of 20-year-olds yesterday.

The number 20 seed had to work much harder than she had so far in the tournament, where she had won 22 consecutive games leading into the match.

She finally pulled it out when the number 26-seeded Sabalenka double-faulted on match point, tossing her racket to the court in frustration.

The last Japanese woman to reach the final eight in a Grand Slam had been Shinobu Asagoe at the 2004 US Open.

Osaka’s compatriot Kei Nishikori advanced to the men’s quarter-finals on his return to the US Open after getting by Philipp Kohlschreiber yesterday.

The 2014 runner-up in Flushing Meadows beat Kohlschreiber 6-3, 6-2, 7-5 to reach the final eight in his second-straight Grand Slam tournament.

Nishikori missed the US Open last year because of a right wrist injury. The number 21 seed from Japan returned to the tour early this year, building his confidence back with a victory in a Challenger Tour event, then reached the final in Monte Carlo and the quarter-finals at Wimbledon, where he lost to eventual champion Novak Djokovic.

He will next face either number seven seed Marin Cilic — who beat him in the 2014 US Open final — or number 10 David Goffin.

Kohlschreiber was denied again in his fifth attempt to win a fourth-round match at the US Open. The German reached his lone Grand Slam quarter-final at Wimbledon in 2012.

Madison Keys returned to the US Open quarter-finals with a 6-1, 6-3 victory over number 29 seed Dominika Cibulkova of Slovakia.

Keys was an Open finalist a year ago and lost to Sloane Stephens. She lost to Stephens again this year in the French Open semi-finals.

The 14th-seeded Keys will play the winner of the Carla Suarez Navarro vs Maria Sharapova match in yesterday’s night session at Arthur Ashe Stadium.

Keys has reached at least the quarter-finals in three of the four Grand Slam tournaments this year. She had six aces and no double-faults yesterday in perhaps her best performance of the tournament.