BASEL, Switzerland - China's Olympic champion Chen Long fought off hard challenge to beat Lee Cheuk-yiu to reach the men's last 16 at the World Championships here on Wednesday.

Chen, also a two-time world champion in 2014 and 2015, took 58 minutes to defeat the 22-year-old Lee from Hong Kong, China 22-20, 21-14.

"It was a tough match, especially the first set," said the 30-year-old Chen. "Fortunately, I have made very good preparation and I know him well because I beat him in a match in January this year."

The third-seeded Chen was the only survivor from China in the men's singles draw after five-time winner Lin Dan and Lu Guangzu crashed out on Tuesday. The other young Chinese player Huang Yuxiang made an early exit on Monday.

"I just want to do what I need to do," he said of the chance of completing a hat-trick of world titles.

He will face on ninth seed Ng Ka Long Angus, also from Hong Kong, China in the next match on Thursday.

In the women's draw, fourth seed Chen Yufei beat Thailand's Pornpawee Chochuwong in straight sets to become the third Chinese player to enter last 16.

The All England champion ousted the 14th-ranked Chochuwong 21-14, 21-19.

Her teammate Cai Yanyan was stopped by South Korea's Kim Ga-eun 21-14, 16-21, 21-10 in a later match.

Sixth seed He Bingjiao and 13th seed Han Yun both advanced on Tuesday with victories over Japan's Aya Ohori and Sayaka Takahashi respectively.

The 21-year-old Chen, who won the bronze in 2017 and was beaten in the quarterfinals last year, will next take on 11th seed Michelle Li of Canada, a 21-19, 21-4 winner over Malaysia's Soniia Cheah.

"I am not in top form today probably because it is my first match," Chen said. "I played too slowly at the beginning of the second set, which gave her many chances."

Chen is drawn to meet second seed Tai Tzu Ying of Chinese Taipei in the quarterfinal should both players win their next match.

Tai, whom Chen defeated in this year's All England Open final, beat Fitriani of Indonesia 21-15, 21-14.