Ajay Jayaram knocked out world number 12 Rasmus Gemke in the second round of the Badminton World Federation (BWF) Swiss Open, breaking the seeds' monopoly on men's singles quarter-final places.
Denmark's Gemke, seeded third, is the only one of eight top-ranked players not to reach the quarter-finals because of Jayaram's efforts.
The Indian player, who has not won a BWF World Tour title since 2015, triumphed 21-18, 17-21, 21-13 in Basel.
"The first set was a see-saw battle, but I did well in the end to pull it out," Jayaram told The Indian Express.
"Had to dig deep and throw in a mix of attacking and defensive play."
Jayaram added that his "focus now is on getting my body ready for tomorrow’s quarter-final".
Thailand's Kunlavut Vitidsarn - seeded eighth - awaits.
The top two seeds - Dane Viktor Axelsen and Malaysia's Lee Zii Jia - both won in straight games.
The same can be said of the top two in the women's singles - Olympic champion Carolina Marín of Spain and India's world champion PV Sindhu.
South Korean Sung Ji-hyun was the sole seed to lose, upset 20-22, 19-21 by Thai 20-year-old Phittayaporn Chaiwan.
Six of the eight women's singles quarter-finalists were among the eight seeded players.
The top seeds also won in the men's, women's and mixed doubles today, with the latter tournament down to the final four.