Following a first-round bye, Wang beat Porntip Buranaprasertsuk of Thailand 21-12, 21-19 to move into the third round.

Despite her status, and being the world's No. 1 player since late last year, Wang hasn't won a title since November and been susceptible to upsets this year.

She lost a classic final to Tine Baun at the All England Championships, then lost early in the Swiss Super Series, and was upset in the Uber Cup final, in which China conceded a first title to South Korea.

Next up is Eriko Hirose of Japan, and a looming quarterfinal against seventh-seeded Lin Wang of China or Pui Yin Yip of Hong Kong, who beat Wang at the Swiss Super Series.

Lin, the bronze medal at last year's worlds in India, defeated Maja Tvrdy of Slovenia 21-7, 21-18.

Petya Nedelcheva of Bulgaria ousted Larisa Griga of Ukraine 21-17, 21-13.

In men's singles, the second-seeded Peter Gade of Denmark and fourth-seeded Chen Jin of China reached the second round.

Chen, a 2009 world runner-up, beat Ville Lang of Finland 21-14, 21-14 while European champion Gade cruised past Daniel Paiola of Brazil 21-10, 21-7.

Chen will next face Kestutis Navickas of Lithuania, who rallied past Kieran Merrilees of Scotland 15-21, 21-13, 21-14.

Gade will have a trickier match against South Korea's Shon Wan Ho, ranked 19th in the world, who defeated Hu Yun of Hong Kong 21-18, 21-13.

“He's been teasing some of the best ones,” Gade said about Shon. “I have to play well to beat him. I need to be patient. He's a strong defensive player, I need to keep my attack a bit back.” The Dane leads 2-0 against Shon but was each time stretched to three sets.

The 107th-ranked Chen Yong Zhao of Singapore caused the first upset of the day by defeating 14th-seeded Chetan Anand of India 21-14, 21-18.

Also, ninth-seeded Boonsak Ponsana of Thailand routed Vladimir Malkov of Russia 21-6, 21-6 and eighth-seeded Simon Santoso of Indonesia beat Przemyslaw Wacha of Poland 21-11, 21-17.