GUANGZHOU (China) - Malaysian world No. 1 Lee Chong Wei stunned the badminton world when he retired on championship point in the men's singles final at the world championships on Sunday.

He had been trailing China's Lin Dan 21-16, 13-21, 17-20 when he decided he could not carry on further owing to injury.

Lee's retirement means Lin has now won his fifth world title, although he was unseeded at this year's event because of his low world ranking following months of inaction after last year's Olympics.

In the women's doubles, the defending champions, Wang Xiaoli and Yu Yang of China, had opened the proceedings by beating Korean eighth seeds Eom Hye Won and Jang Ye Na 21-14, 18-21, 21-8 to retain their title.

But there was a stunning upset in the women's singles, with Thailand's Ratchanok Intanon beating Olympic champion Li Xuerui 22-20, 18-21, 21-14 in the final.

The host nation also suffered a reversal in the mixed doubles, with third-ranked Indonesians Tontowi Ahmad and Liliyana Natsir defeating the top seeds Xu Chen and Ma Jin 21-13, 16-21, 22-20.

The Indonesians made it two wins in two finals as sixth seeds Mohammad Ahsan and Hendra Setiawan romped to 21-13, 23-21 victory over third-seeded Danes Mathias Boe and Carsten Mogensen in the men's doubles.