HAMBURG, Germany (AFP) - World number one Roger Federer admitted he had few problems as he outclassed Finland's Jarkko Nieminen in straight sets here at the Hamburg Masters Series on Wednesday.

The Swiss master needed less than an hour to see off his opponent 6-1, 6-3 and in the 18 sets the pair have now contested, during their nine previous matches, Nieminen has yet to win a single one.

"It was a good performance, I was happy with the way I served from the baseline," said Federer, who beat main rival Rafael Nadal in last year's final here.

"I have had so much success here, I have a good feeling about the place. When my first point went straight down the line, I thought 'This place works well for me'.

But other seeds fell elsewhere at the Am Rothenbaum stadium on a day of upsets.

Seventh seed James Blake was knocked out 4-6, 6-3, 6-3 by Serbia's Janko Tipsarevic and 13th-seed Tommy Robredo also crashed out to Croatia's Ivo Karlovic after losing 3-6, 6-2, 7-6 (7/3).

And Frenchman Jo-Wilfried Tsonga, the 14th seed, made a sharp exit when he went down in straight sets 6-2, 7-5 to Sweden's Robin Soderling.

"I just didn't play as well as I wanted to," confessed the Australian Open finalist. It's not been a bad season so far, but I have to keep improving and working on my game."

But former world number one Marat Safin continued his comeback with a straight-sets win over ninth-seed Tomas Berdych in the second round. The Russian is building some momentum here having qualified through the main draw.

He has plummeted down the rankings to 89th after suffering a series of injuries, but hit four aces on his way to knocking out Berdych, 11th in the world, 7-5, 6-4 in 90 minutes.

The 28-year-old Russian, who was runner-up here in 2000 and 2002, is now on course to meet Carlos Moya in the 3rd round if the Spaniard beats Belgium's Oliver Rochus in his second round match.

But there were no problems for Argentinian Juan Monaco who made it through to the third round after the 12th seed breezed past Italy's Simone Bolelli 6-2, 6-1.

He will play another Italian in the third round when he faces Andreas Seppi who removed French number one and eighth seed Richard Gasquet on Tuesday.

Local hero Nicolas Kiefer reached the Hamburg third round for the first time since 2001 Wednesday after he beat World No. 10 and last week's Rome finalist Stanislas Wawrinka 7-5, 7-5 on Center Court.

Germany's Kiefer will now play fourth seed Nikolay Davydenko in the third round on Thursday.