Japanese defending champion Akane Yamaguchi reached the women's singles quarterfinals of badminton's BWF World Championships on Thursday by beating 14th-seeded compatriot Sayaka Takahashi in straight games.

Yamaguchi, the winner last year in Huelva, Spain, and the top seed, was made to work before taking the first game 21-18 but cruised 21-7 in the second to clinch the round-of-16 win in 36 minutes at Tokyo Metropolitan Gymnasium.

"I didn't rush and could play at my pace," said Yamaguchi, who varied the speed on her shots in the second game when she scored seven straight points.

Japan's Akane Yamaguchi is pictured in action against compatriot Sayaka Takahashi in the women's singles third round at badminton's BWF World Championships at Tokyo Metropolitan Gymnasium on Aug. 25, 2022. (Kyodo)

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Next up for Yamaguchi will be the fifth seed, Spain's Carolina Marin. The three-time world champion and 2016 Rio de Janeiro Olympic gold medalist missed the Tokyo Olympics through injury.

"I'll be playing into her hands if I back off. I'll want to avoid holding back in either my play or my feelings and be aggressive," Yamaguchi said.

Defending champion Akane Yamaguchi (R) of Japan meets compatriot Sayaka Takahashi at the net after Yamaguchi's victory in the third round of the women's singles at the world badminton championships in Tokyo on Aug. 25, 2022. (Kyodo) ==Kyodo

Japan's sixth-seeded Wakana Nagahara and Mayu Matsumoto reached the women's doubles quarterfinals for the fourth straight tournament, easing past China's 13th seeds, Du Yue and Li Wenmei, 21-13, 21-9 and staying on course to reclaim the title they won in 2018 and 2019.

"As we played, we were thinking about how to manage the flow of the game to make the most of our attacks," Nagahara said after they made adjustments from their previous match, playing for longer rallies and patiently waiting for ideal opportunities to attack.

Japanese fifth seeds Chiharu Shida and Nami Matsuyama also reached the last eight, holding off Malaysia's 10th seeds Pearly Tan and Thinaah Muralitharan 21-16, 21-16.

Reigning men's doubles champions and second seeds Takuro Hoki and Yugo Kobayashi of Japan reached the quarters by beating Scotland's Alexander Dunn and Adam Hall 21-12, 21-14.

In mixed doubles, Tokyo Olympic bronze medalists and third seeds Yuta Watanabe and Arisa Higashino advanced to the quarters with a 21-12, 21-19 win over Dutch 15th seeds Robin Tabeling and Selena Piek.