Second seed David Nalbandian was upset 3-6, 6-3, 6-1 by Chilean Fernando Gonzalez in the quarter-finals of the Vienna Open on Friday.

Fifth seed Gonzalez next faces Andy Roddick [Images] after the third-seeded American defeated Austrian left-hander Juergen Melzer 6-4, 6-3.

Holder and top seed Ivan Ljubicic of Croatia eased past Swiss Stanislas Wawrinka 6-3, 6-2 to clinch a meeting with unseeded Slovak Dominik Hrbaty, who ousted Stefan Koubek of Austria 6-1, 5-7, 6-2.

Argentine Nalbandian lacked the serving power of Gonzalez, who took advantage of several errors by his opponent in the third set.

The two South Americans had looked at home for much of the match, slicing their backhands from the baseline on the slow indoor court.

"He dominated until 3-3 in the second set. I went 4-3 up, got a break and was back in the match," Gonzalez told reporters. "Then he didn't play so well. I think he was a little bit tired because we played many long points."

Roddick had to work hard to get on top against Melzer.

"I thought I played okay," said the American. "I was a little disturbed early just because he's a different kind of player, especially being a lefty.

"His repertoire of shots was keeping me off-balance and I thought he was striking the ball pretty well. But I feel confident going into tomorrow."

Ljubicic struck 11 aces and was never pressured by Wawrinka, who rallied well when he had the chance but had nothing in his arsenal to cause the world number three serious problems.

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