Ratchanok Intanon knocked out the top seed in the women's tournament ©Getty Images

The top two women's seeds were knocked out on quarter-finals day at the Badminton World Federation China Open.

Both top-ranked Tai Tzu-ying of Chinese Taipei and India's second ranked defending champion P. V. Sindhu suffered defeats as the Super Series tournament continued at Fuzhou's Haixia Olympic Sports Center.

Tai fell to Thailand's former world number one Ratchanok Intanon, the eighth seed who won the World Championship in 2013.

Intanon prevailed from behind 10-21, 21-9, 22-20.

She will now play Japan's Akane Yamaguchi, the fifth seed who saw off Chinese qualifer Ji Shuting 21-11, 21-19.

Sindhu, the Rio 2016 silver medallist, was beaten by another home qualifier with her loss meaning a repeat of last year's Olympic final was not booked for the last four.

Gao Fangjie came through 21-11, 21-10 and will now face Spain's Rio gold medallist and fourth seed Carolina Marin, a 21-15, 22-24, 22-20 winner over China's seventh seed He Bingjiao.

Men's top seed Viktor Axelsen marched into the semi-finals ©Getty Images
Men's top seed Viktor Axelsen marched into the semi-finals ©Getty Images

In the men's draw, Denmark's top seed and reigning world champion Viktor Axelsen marched through to the last four by knocking out Chinese Taipei's fourth seed Chou Tien-chen 21-17, 21-14.

His reward is a semi-final date with Hong Kong's unseeded hope Angus Ng, who upset triple Olympic silver medallist Lee Chong Wei of Malaysia.

Ng beat the seventh seed 21-12, 15-21, 21-19.

China's home hopes rest with Olympic champion Chen Long, who knocked out compatriot Shi Yuqi.

Chen, seeded sixth, beat his fourth seeded opponent 21-13, 16-21, 21-14.

He will now play South Korea's second seed Son Wan-ho, who was a 21-14, 12-21, 21-18 winner over Hong Kong's qualifier Lee Cheuk Yiu.

The semi-finals will be played tomorrow.