By Sanjay Rajan

CHENNAI, India - Spanish world number two Rafael Nadal and Austrian Stefan Koubek moved into the Chennai Open quarter-finals on Thursday.

While left-hander Koubek thumped seventh-seeded Thai Paradorn Srichaphan 6-1 6-2 in 47 minutes in his second round match, top seed Nadal was stretched by Indian wildcard Karan Rastogi in the first set before winning 6-4 6-1.

French Open champion Nadal, dressed in a brightly coloured sleeveless tee-shirt and capris, closed the contest against his 480th ranked opponent in 84 minutes on centre court and hit balls into the stands in celebration afterwards.

"It was a nice game for him, playing without pressure is a lot easier," 20-year-old Nadal told a news conference.

"He had nothing to lose, and he played aggressively," Nadal added. "I had to play hard in the first set."

Rising Indian talent Rastogi, egged on by 5,000-strong crowd, played deep and held his serve until Nadal broke him in the ninth game with an exquisite forehand passing shot.

A fired-up Nadal wrapped up the second set in quick time with breaks in the third and fifth games.

"I did better than I expected," 20-year-old Rastogi said with a smile. "In the first set I proved to myself I can play at this level."

Nadal will next meet 106th ranked Italian Davide Sanguinetti, who defeated eighth-seeded Frenchman Nicolas Mahut 7-6 3-6 6-3.

Koubek displayed powerful groundstrokes to dominate Paradorn, who is recovering from the wrist injury that forced him out of the singles at last month's Asian Games.

"I played solid tennis," Koubek told a news conference. "It was maybe easy because Paradorn was injured...everything went right for me."

Paradorn, four times a finalist here, said: "It was difficult playing Stefan with the injury because he was playing more to my back hand.

"I thought I was ready for the tournament, guess I wasn't. I don't know about the Australian Open, I've got two weeks to go."

Koubek will next meet fourth-seeded Frenchman Julien Benneteau, who beat Russian Igor Andreev 7-6 6-2.

Sixth-seeded Frenchman Fabrice Santoro also advanced with a 6-4 6-2 triumph over German Bjorn Phau.

He faces third seed Xavier Malisse of Belgium in the last eight, while former world number one Carlos Moya plays Croat Ivo Karlovic to complete the line up.