Qualifier Sourabh Verma pulled off another stunner at the Indian Open Super Series badminton here on Thursday, and he is joined in the quarterfinals by Guru Sai Dutt with an impressive victory at the Siri Fort Sports Complex here.

India's top women's doubles pair Jwala Gutta and Ashwini Ponnappa, however, was beaten in the first match after getting a bye into the second round. Also bowing out was Parupalli Kashyap, ranked 24th in the world.

Continuing his giant-killing spree, the little-known Madhya Pradesh youngster Sourabh upset seventh-seeded Tago of Japan 21-19, 18-21, 21-11.

Dutt showed the door to Yuhan Tan of Belgium with 21-13, 14-21, 21-13 victory.

Kashyap went down to second-seeded Indonesian Taufiq Hidayat 17-21, 19-21.

After the shock exit of Saina Nehwal Wednesday, much was expected from Commonwealth Games gold medallists Gutta and Ponappa, but the eighth-seeded Indian pair lost 20-22, 18-21 against Eei Hui Chin and Pei Tty Wong of Malaysia.

Sourabh, who knocked out Indonesian Sony Dwi Kuncoro, a bronze medallist at Athens Olympics in the first round Wednesday, will now face top-seeded Malaysian Lee Chong Wei, who beat Korean Lee Hyun 21-13, 21-17.

Dutt will take on eighth-seeded from Hong Kong Yun Hu, who defeated compatriot Yan Kit Chan 21-16 21-14.

Sourabh quietly made his way up when fancied Indians, including favourite Saina Nehwal, fell by the wayside. The Pullela Gopichand Academy trainee, came through tough qualifiers, beating a Malaysian, on the way.

The winner of an All-India Senior Ranking tournament before coming here, Sourabh said he came into the tournament thinking of putting up his best.

"Beating Sony Dwi Kuncoro yesterday gave me confidence. It is amazing how you feel when you beat a top international player at this level," an exhausted Sourabh said after the hour-long duel against Tago.

"My legs were a bit tired after yesterday's match but I stayed in the game and wanted to be aggressive in the decider.

"I am very happy to have made it to the quarterfinal in my first Super Series event and this will motivate me to do better."

It was a close battle and Tago led 4-2 in the first game. The Japanese kept himself in front, but Sourabh was never too far behind. From 15-all, Sourabh stitched together four points and the game was his.

Sourabh was good at retrieving and played and used the drop shot imaginatively. He engaged Tago in long rallies pushing him to the back court.

The Indian looked in control in the second game and led 16-13, before losing the plot. Tago fought back to reel off seven points to draw parity.

In the decider, Sourabh stepped up his game and opened a massive 6-0 lead. From there on the Indian took charge and wrapped up the game without any hiccups.

"I have nothing to lose," Sourabh said on facing Chong Wei next.

Datt was also elated with his performance.

"I have been training hard. I reached the quarterfinal of Denmark Open in 2009 and making it to the last eight here is good," he said.

"I was not at my best. I will hopefully will have enough time to recover and get ready for the next match."

Gutta and Ponnappa said that a few mistakes cost them the match against the former World No. 1 pair.

"It is disappointing, especially since there were a lot of expectations from us. We were comfortable out there in the middle, but we lost because of some silly mistakes," Gutta said.

In another men's singles quarterfinal, third seed Peter Gade will take on Takuma Ueda of Japan. Gade got the better of Japanese Sho Sasaki 21-12, 21-17 while Ueda beat Hong Kong's Wing Ki Wong 21-19, 18-21, 21-16.

Hidayat will face South Korean sixth seed Sung Hwan Park, who defeated Wan Ho Shon 21-12, 21-17.

The men's doubles pair of Rupesh Kumar and Sanave Thomas went down to Yohanes Rendy Sugiarto and Afiat Yuris Wirawan of Indoensia 19-21, 18-21.

In the mixed doubles, India's Akshay Diwalkar and Pradnya Gadre went down fighting to Peng Soon Chan and Liu Ying Goh of Malaysia 18-21, 24-22, 12-21.

Gadre, pairing with Jyotshna Polavarapu in women's doubles, lost to top seed Miyuki Maeda and Satako Suetsuna 8-21, 16-21.

In the men's doubles, Attri Manu and Jishnu Sanyal were beaten by top-seeded Malaysians Kien Keat Koo and Boon Heong Tan 21-9, 21-14

There were a string of upsets in the women's singles. Saina's slayer Ai Goto lost to Juan Gu of Singapore 21-17, 8-21, 25-23 in a thrilling match.

Thailand's Porntip Buranaprasertsuk beat Japan's Eriko Hirose, seeded fifth, 21-9, 15-21, 22-20 in a cliffhanger while second seed Tine Baun, who is coming back an injury, went down to Jiayuan Chen of Singapore.

In another mixed doubles second round match, Pranav Chopra and Prajakta Sawant lost to Japanese Kenta Kazuno and Ayaka Takahashi 14-21, 18-21.