Ng Ka Long celebrates after ousting Chen Long ©Getty Images

Both the men's and women's top seeds were knocked out on quarter-finals day at the Badminton World Federation (BWF) Singapore Open today.

In the men's draw, China's top ranked player Chen Long was defeated by Hong Kong's Ng Ka Long in the Super Series event, going down 21-14, 21-18.

The double world champion had needed three games in his first and second round victories and his luck finally ran out today.

Ng will now contest a semi-final with another non-seed, South Korea's Son Wan-ho, who battled past China's Tian Houwei 11-21, 21-15, 21-19.

China's second seed Lin Dan, the double Olympic champion, is now favourite for the title after he came through 21-18, 21-14 against Indonesia's Tommy Sugiarto.

Another Indonesian, Sony Dwi Kuncoro, continued his fine run by ousting China's Wang Zhengming 24-22, 12-21, 21-16.

The qualifier has now won a trio of three game matches in the main draw and will go up against Lin in the last four.

Akane Yamaguchi ended the hopes of Spain's top seed Carolina Marin
Akane Yamaguchi ended the hopes of Spain's top seed Carolina Marin ©Getty Images

In the women's competition, Spain's top seed and two-time world champion Carolina Marin was beaten in three games by Japan's Akane Yamaguchi, 13-21, 21-18, 21-18. 

The Japanese will face Thailand's Malaysia and India winner Ratchanok Intanon, who kept her bid for three straight Super Series titles alive by knocking out compatriot Porntip Buranaprasertsuk 21-12, 21-18.

Defending champion Sun Yu kept her hopes of retaining the title alive by beating South Korean Sung Ji-hyun 21-15, 19-21, 21-19.

She will meet team-mate He Bingjiao who ended the hopes of American Zhang Beiwen, 21-16, 21-15.

The semi-finals will be played at the Singapore Indoor Stadium tomorrow.