Twice defending champion Chen Long breezed past Sony Dwi Kungcoro in straight games at the World Badminton Championships but five-time titlist Lin Dan had to sweat in the fight for his spot in the last 16.
Chen, also the gold medalist in last year's Rio Olympics, raced to a 21-13, 21-9 victory over the 33-year-old Indonesian veteran. He will next face India's 13th seed Ajay Jayaram.
"I am so happy to have won in only two games, but I want to be prepared for the whole tournament and tomorrow's games," said Chen, the tournament's fifth seed.
Lin, nicknamed "Super Dan" by his fans, was pushed hard by Denmark's Emil Holst, fighting back from one game down to win 19-21, 21-8, 21-16.
The 33-year-old dropped a four-point lead in the deciding game to let Holst level the score at 16-16. But the twice Olympic champion then gave no chance to Hoslt, scoring five points in a row to close out the match after 81 minutes.
"He created a lot of trouble for me," Lin said. "He played smartly in defense. I found it very hard to score points because he could always save my attacking shots.
"Of course, my motivation in tournaments will always be the gold medal and here that is no different. Along the way you will always have to play very hard matches so I am very pleased to come through this one."
The seventh seed will fight for a quarterfinal berth against England's 16th seed Rajiv Ouseph, who beat India's Sameer Verma 22-20, 21-9.
Ouseph, ranked 20th in the world, looked forward to the match on Thursday.
"It doesn't get much bigger than playing the greatest player that's ever played, and in the World Championships, so its very exciting and the pressure's off me a bit, so I'll just try and enjoy myself and see what I can do."
China's Shi Yuqi and Tian Houwei also reached the third round, with fourth seed Shi beating Brazil's Ygor Co, 21-23, 21-10 and 10th seed Tian defeating Russia's Vladimir Malkov 21-17, 21-14.
Top seed Son Wan Ho of South Korea routed Gergely Krausz of Hungary 21-13, 21-9 while third seed Viktor Axelsen of Denmark eliminated Finland's Eetu Heino 21-15, 21-15.
In the women's competition, Olympic champion Carolina Marin of Spain crushed Yip Pui Yin of Hong Kong, China, 21-5, 21-7. China's He Bingjiao, the fourth seed also cruised into the last 16.