NEW YORK - Two-time U.S. Open champion Naomi Osaka exited the tournament in the fourth round Monday with a 6-1, 6-4 loss to No. 2 seed Elena Rybakina of Kazakhstan.
Japan's former world No. 1 gave up an early break on her second service game and from there could not gain an upper hand over the in-form Rybakina, who wrapped up the contest in 66 minutes.
The 13th-seeded Osaka was "sad that I couldn't do what I set out to do" but sounded a positive note about the loss.
"I think I am happy that I'm taking losses differently. I'm trying to learn from them a lot more," Osaka said. "I had an opportunity to play this Slam, I got as far as I could, so it's only up from here."
Rybakina, who won her second major at this year's Australian Open, will secure the world No. 1 ranking if she beats quarterfinal opponent Zheng Qinwen of China.
Eri Hozumi and Slovenian partner Andreja Klepac were beaten in the women's doubles third round, while Miyu Kato and Taiwan's Wu Fang-hsien also lost, leaving Japan without a player in the singles or doubles draws.
