The Olympic bronze medallist from last month's Rio 2016 Games was the second seed at her home tournament but is now the top ranked player after the withdrawal of Spain's Carolina Marin, who won gold in Brazil.

She won the tournament in 2015 and remains on course to successfully defend her crown after ousting China's Chen Yufei 21-13, 21-16.

Her biggest challenger in Tokyo could be Thailand's Ratchanok Intanon, who also made the last eight after a 21-11, 21-10 success over Japan's Minatsu Mitani.

Intanon, the third seed, is hoping to win a fourth Super Series title this season after previous successes in India, Malaysia and Singapore.

Sixth seed Akane Yamaguchi of Japan set up a quarter-final meeting with Okuhara after beating Linda Zechiri of Bulgaria 21-11, 21-13.

In the men's tournament, Malaysia's top seed Lee Chong Wei breezed through to the last eight with a 21-8, 21-16 win over Chinese qualifier Qiao Bin.

The triple Olympic silver medallist was joined in progressing by Denmark's Viktor Axelsen, the second-seeded European champion and Rio 2016 bronze medallist, who got the better of Prannoy Kumar of India 21-16, 21-19.

Third seed Jan Ø. Jørgensen joined his compatriot in the next round thanks to a 21-14, 21-13 win over South Korea's Lee Dong-keun, but Chinese Taipei's fifth seed Chou Tien-chen was knocked out.

He was ousted by Thailand qualifier Khosit Phetpradab, 13-21, 21-15, 21-17 and joined fourth-seeded Chinese player Tian Houwei, who lost in the first round yesterday, in making an early exit from the tournament.

The competition, the seventh Super Series event of the season, will continue tomorrow in the Japanese capital, the host city of the 2020 Summer Olympics and Paralympics.