India's Parupalli Kashyap upset third-seeded Boonsak Ponsana of Thailand 21-9, 21-19 to move into the quarterfinals of the Denmark Open Super Series badminton tournament.
Unseeded Kashyap, who has been in an outstanding form this season and won singles bronze in the just concluded Commonwealth Games, took just 31 minutes to overpower the World No.10.
Kashyap is down 28 rungs from his famed rival in the world rankings but proved to be the better one Thursday.
The Hyderabadi made a strong start, opening up a 6-1 lead in the first game, and consolidated it by dictating the flow of the game in long rallies.
Kashyap raced ahead 7-2 in the second game, before Ponsana made a comeback and took the lead at 10-9. The two fought fiercely from there on, but Kashyap broke free from 13-all, taking four points in a row. Kashyap displayed his soft touch at the net and made the Thai player struggle for every point before the Indian went on to close the match.
Kashyap will next face world no.26 Pengyu Du, the only Chinese in the draw, for a place in the semi-final.
The two other Indians in the singles draw, Chetan Anand and Anand Pawar, are already out.
In other men's singles matches, Indonesia's Taufik Hidayat inched closer to the final with a comprehensive win over local hope Joachim Persson 21-15, 21-19. He now faces a tricky match against 2010 All England runner up Kenichi Tago of Japan in the quarters.
In the women's singles, Denmark's Tine Baun Rasmussen, seeded second, was the biggest name to fall, losing to Boonsak's sister Salakjit 16-21, 20-22.
China's World No. 2 Wang Yihan and the top seed here faced no such problems as she beat Bulgaria's Linda Zechiri 21-11, 21-9 for a place in the last eight where she meets compatriot Xuerui Li.