Rio Olympic champion Chen Long finally got himself into a hard-fought contest at the 2019 Badminton China Open after a relatively easy run to the quarter-finals, where he edged out Ng Ka Long of China's Hong Kong 21-13, 21-16 under the watchful eye of his wife on Friday night.

Victory, though, has delivered the fifth seed Chen a tougher assignment: a semifinal against the Japanese top seed Kento Momota, who had a far easier time of it against compatriot Kanta Tsuneyama, winning 21-11, 21-8.

Meanwhile, Denmark's Anders Antonsen caused the biggest upset of the day after the 22-year-old overwhelmed No. 2 seed Chou Tien Chen of Chinese Taipei 21-17, 21-11 in another quarterfinal bout.

On women's part, China's He Bingjiao failed to resist three-time World Champion Carolina Marin's late rally in their last eight clash as she suffered an agonizing loss to the Spaniard 21-11, 12-21, 15-21 despite an early lead.

Marin had just recovered from a cruciate ligament injury and insisted the win means she is back at full fitness. "I don't feel any pain, so I just want to keep improving my game."

Marin will next take on Sayaka Takahashi of Japan, who knocked out sixth-seeded Ratchanok Intanon of Thailand.

Current world No. 2 Tai Tzu-ying of Chinese Taipei overcame a slow start as she beat Thailand's Busanan Ongbamrungphan 21-17, 21-10 to storm into the last four. 

Next up for Tai is Chinese third seed Chen Yufei, who outclassed another Thailand shuttler Pornpawee Chochuwong 22-20, 21-13 earlier in the day.