Federer is trying to win his home-town event for the first time

Federer, playing in his home-town event, came through a dramatic second-set tie-break to beat David Ferrer 6-3 7-6 (16-14).

Nalbandian was beaten by Stanislas Wawrinka of Switzerland 7-6 (9-7) 6-2.

Wawrinka will next play third seed Fernando Gonzalez, who beat Juan Martin Del Potro of Argentina 5-7 6-4 6-4.

"He played better than me today, I was always on the defensive," said Nalbandian, who is sixth in the race for the season-ending Masters Cup in China next month.

I think I was trying to risk a bit more in front of my home crowd today Roger Federer

"I wasn't able to play my game but I'm a bit closer to Shanghai and I have next week in Paris."

Federer has been in magnificent form in recent weeks but was given a tougher test by fifth seed Ferrer.

The world number one was broken three times and saved six set points in the second-set tie-break before winning his 22nd straight match.

"It was surely luck some of the time," Federer admitted. "It's not easy to play such a long tie-breaker.

"I think I was trying to risk a bit more in front of my home crowd today, so I'm just lucky that it paid off in the end."