China's Shi Yuqi beat the 11th seed Rasmus Gemke of Denmark to reach the last 16 at the World Badminton Championships here on Tuesday.
Shi, who returned to action at the tournament after a 10-month suspension, took 46 minutes to down the Dane 21-13, and 21-16 in the second round.
The 2018 worlds finalist has slipped to 25th in the world rankings after a long absence, but he proved much stronger than what the ranking place has suggested.
He rated his performance "7 out of 10", one point more than his first-round show.
"I played much better than the first match, although there is still a long way from my best badminton," he said.
The Chinese national champion struggled in his victory over lowly-ranked Ade Resky Dwicahyo of Azerbaijan on Monday, the first match after his suspension was lifted in early July. He was forced to fight back from 14-9 behind in the first game to win, reports Xinhua.
Shi was banned from all competitions last October for making "inappropriate remarks" about the withdrawal from the Thomas Cup semifinal against Japan's Kento Momota.
Shi will next take on the sixth seed Anthony Sinisuka Ginting of Indonesia, who crushed Georges Julien Paul of Mauritius 21-10, 21-16. Shi has kept a perfect record in their six previous meetings.
"He is a tough player and always makes you suffer," Shi said. "That will definitely be a difficult match."
Lu Guangzu crashed out of the tournament after losing to Wang Tzu Wei of Chinese Taipei 21-18, 21-16.
Wang Yilyu and Huang Dongping, who had upset teammates Zheng Siwei/Huang Yaqiong to win the Olympic mixed doubles gold last year, opened their campaign with a difficult win, beating Malaysian duo Chen Tang Jie/Peck Yen Wei 21-14, 12-21, 21-11.