The Spaniard, seeded second in the women's singles tournament, was involved in a marathon contest with the Thai player, which lasted nearly an hour and 20 minutes.

Intanon, the 2013 world champion, won the opening game before Marin fought back to level.

But it was the Thai star who progressed to the last four as she wrapped up a 22-20, 13-21, 21-18 succes.

Number one seed Tai Tzu Ying safely progressed to the semi-finals as she overcame PV Sinhu, who lost to Marin in the final at last year's Olympic Games in Rio de Janeiro, 21-14, 21-10.

Sung Ji-hyun of South Korea, bronze medallist at the 2015 World Championships, is also through after she beat India's Saina Nehwal, seeded eighth, 22-20, 22-20.

The semi-final line-up was completed by Japan's Akane Yamaguchi, who ousted fourth seed Sun Yu of China, recovering from dropping the opening game to claim a 21-23, 21-14, 22-20 triumph.

Perennial Olympic silver medallist Lee Chong Wei of Malaysia put in another ominous display for the rest of the field in the men's singles as he swept aside China's Tian Houwei in straight games.

Lee, the top seed, made light work of his Chinese opponent with a 21-12, 21-15 win.

He was joined in the last four by China's Shi Yuqi, who accounted for Kazumasa Sakai of Japan 21-13, 21-4.

Sixth seed Lin Dan, also of China, endured a torrid start to his match with Denmark's Viktor Axelsen, losing the first game by a convincing margin before he recovered to win 8-21, 21-14, 21-15.

Chou Tien Chen of Chinese Taipei also needed three games to get past his opponent as he emerged with a 21-19, 16-21, 21-8 victory against Tanongsak Saensomboonsuk of Thailand.

The event in Birmingham continues tomorrow.