Federer into last eight of Swiss tournament

Roger Federer rolled into the quarter-finals of the 1.2 million Swiss Indoors tournament Thursday with a 6-1 6-4 victory over unseeded Argentinian Juan Martin Del Potro.

Switzerland’s world number one has 12 grand slam championships and 51 singles titles, but it wasn’t until 2006 that he finally broke through here in his home country.

A runner-up at this event in 2000 and 2001, Federer has now won seven straight matches here and appears motivated to defend his championship.

The Swiss superstar also may be still feeling the sting of Sunday’s stunning loss to unseeded David Nalbandian in the Madrid final.

That’s bad news for Nicolas Kiefer, who awaits Federer in the quarter-finals after a 6-3 6-2 win over Stefan Koubek.

The German played well against Federer in the Madrid semi-finals last week but eventually succumbed 6-4 6-4 and fell to 3-9 in the all-time series.

Second seed Fernando Gonzalez of Chile was the first player to advance to the quarter-finals on Thursday, defeating Croatian Roko Karanusic 6-4 7-6 (7-5) in the first ever meeting between the two.

Gonzalez won this event in 2005 and reached the final a year ago before running into Federer, a player he had never beaten in 10 games.

The 27-year-old also reached the final here in 2002, but lost to Nalbandian.

Gonzalez’s quarterfinal foe will be unseeded Jarkko Nieminen, who upset sixth seed Guillermo Canas, 6-4 3-6 7-5.

The native of Finland is trying to reach his third semi-final of the season. But it won’t be easy against Gonzalez, who has won all four of their meetings, taking nine out of 10 sets.

Ivo Karlovic turned in the biggest upset of the tournament Thursday as he rallied for a 4-6 7-6 (7-4) 6-4 win over fourth-seeded American James Blake.

The hard-serving Croat blasted 24 aces en route to his third consecutive win against Blake, who also was upset in the second round at Madrid last week.

Moreover, this is the third time in as many appearances here that Blake has failed to make it out of the second round.

Karlovic has 1,234 aces this season which is the second most since the ATP began tracking the statistic in 1991. His countryman, Goran Ivanisevic holds the all-time record with 1,477 in 1996.

While it’s unlikely Karlovic will challenge for that record with the season’s end fast approaching, he can take pride in the fact that he’s averaging 20.6 aces per match in 2007. Ivanisevic averaged 15.4 in his record-breaking year.

Fifth-seeded Tomas Berdych will face Karlovic in the quarter-finals after securing a 7-5 6-4 win against unseeded Stanislas Wawrinka. The Czech beat Karlovic in their only meeting last month in Bangkok.

In the remaining second-round match, eighth seed Paul-Henri Mathieu of France rallied for 6-7 (7-9) 6-4 6-1 victory over Russian Andrey Golubev.

Mathieu’s quarter-final foe will be Marcos Baghdatis, who also came from behind to defeat Agustin Calleri, 6-7 (1-7) 6-3 6-3.

First prize is 172,000.