The Chinese star was the top seed for the men’s event at the Titan Gym on the campus of California State University.

He was surprised by an impressive performance from South Korea’s Lee Dong Keun, who claimed the opening game of the match 21-13.

Dan trailed 19-12 in the second game to stand on the brink of defeat, but ultimately retired from the match to send Lee through at the Badminton World Federation Super 300 event.

Lee will now face Israel’s Misha Zilberman, who came from behind to beat Denmark’s Kim Bruun 13-21, 21-13, 21-15.

France’s Brice Leverdez and Denmark’s Jan O Jorgensen clashed in one of the highest profile matches in the first round of the men’s singles competition.

Leverdez, the third seed in the draw, was able to claim a 21-16, 21-16 victory to reach the second round.

He will face the challenge of South Korea’s Heo Kwang Hee, who edged England’s Toby Penty 19-21, 21-19, 21-18.

Top seeds were largely untroubled in the women’s draw.

Home favourite Beiwen Zhang, the top seed in the women’s singles draw, eased through her opening match.

The American overcame Germany’s Yvonne Li by a 21-13, 21-14 score.

Japan’s Sayaka Sato saw off the challenge of the US’ Jennie Gai in impressive fashion, with the second seed booking her place in the next round.

Sato emerged as a 21-15, 21-17 winner.

She will now face China’s Li Xuerui, who won 21-15, 21-15 against Canada’s Brittney Tam.

Canada’s Michelle Li proved untroubled in her opening match of the tournament, as she eased to a 21-14, 21-16 success against the American hopeful Crystal Pan.

Her reward will be an all-Canadian clash with Rachel Honderich, who beat India’s Anura Prabhudesai 21-9, 21-17.

Spain’s Beatriz Corrales was among the seeded players to suffer defeat, as she suffered defeat to China’s Gao Fangjie.

Gao secured a straight games 21-8, 21-11 victory over the eighth seed to reach the next round.