The Thai player eased through against South Korea's Woo Seung-hoon, romping to a 21-11, 21-9 win in a little over 30 minutes.

He is now due to play China's number five seed Sun Feixiang in the last four after he defeated number nine ranked Koki Watanabe of Japan in straight games.

Sun was victorious 21-17, 21-11 and will now look to end Wangcharoen's charge to the title.

A final with both of the top seeds remains a possibility as Malaysia's number two Lee Zii Jia is also safely through to the semi-finals.

He ended the interest of the last European player in the draw, France's Toma Junior Popov, with a 21-12, 21-18 success.

His semi-final opponent will be Indonesian Chico Aura Dwi Wardoyo, a 21-18, 21-14 winner today against Ng Zin Rei Ryan of Singapore. 

In the women's tournament, China's favourite Chen Yufei continued her pursuit of the title by reaching the last four.

The number two seed, the top ranked player left following the exit of Malaysia's Goh Jin Wei yesterday, was too good for her team-mate Yue Han, winning 21-16, 21-15.

Her biggest challenge looks set to be Thailand's Pornpawee Chochuwong, who progressed after knocking out Singapore's Yeo Jia Min, 21-11, 21-11.

Chen will play South Korea's Kim Ga-eun in the last four, who progressed thanks to a 21-17, 21-11 victory over China's Cai Yanyan.

Chochuwong will now meet Natsuki Oie of Japan, who ended the chances of another Chinese player, Gao Fangjie, with a 22-20, 21-18 win.

The last four matches are due to be played in Bilbao tomorrow.