Defending champion Saina Nehwal advanced to the quarter-finals of the Indonesian Open Super Series, registering a straight-game victory over Petya Nedelcheva in the second round in Jakarta on Thursday.

The fourth seeded Indian needed just 31 minutes to dispose off Petya, winning 21-18, 21-9.

She takes on the winner of the match between eighth seed Tine Baun and Japan's Ayane Kurihara in Friday's quarter-finals.

In the first game, Saina opened up a four-point lead at 6-2 and though the Bulgarian caught up at 12, the Indian was successful in keeping her nose ahead to pocket the game.

The 21-year-old Indian turned more aggressive in the second game and after leading 5-2 had things her way.

Saina won the Indonesian Open in 2009 and 2010.

Meanwhile, the Commonwealth Games gold medallist pair of Jwala Gutta and Ashwini Ponnappa continued with their indifferent form, and lost their second round match to the sixth seeded Indonesian combo of Meiliana Jauhari and Greysia Polii.

The unseeded Indian pair lost 20-22, 21-18, 18-21, in 68 minutes.

Jwala and Ashwini had lost in the first round of the Singapore Open, to the South Korean pair of Kyung Eun Jung and Ha Na Kim.