Hamburg, Germany (My Sportsbook) - The world's top-two stars -- Swiss Roger Federer and Spaniard Rafael Nadal -- were a pair of second-round winners Wednesday at the $2.955 million Masters Series Hamburg, a clay-court French Open tuneup.

The reigning Hamburg champion Federer whipped Finn Jarkko Nieminen 6-1, 6-3, while the three-time French Open titlist Nadal got past Italian Potito Starace 6-4, 7-6 (8-6) at Rothenbaum. Federer is now a perfect 9-0 lifetime against Nieminen.

Both Federer and Nadal enjoyed opening-round byes this week.

Federer beat the clay-court king Nadal in last year's Hamburg finale to record his fourth title here in six years (2002, 2004-05, 2007). Nadal topped Federer in a clay-court final in Monte Carlo just last month.

Top-10 upsets came when improving Serbian Janko Tipsarevic tripped up seventh- seeded American James Blake 4-6, 6-3, 6-3 and former world No. 1 Russian Marat Safin, a qualifier this week, took out ninth-seeded Czech Tomas Berdych 7-5, 6-4. Safin reached Hamburg finals in 2000 and 2002.

Milder Day-4 upsets occurred when 6-foot-10 Croat Ivo Karlovic saved a match point before toppling 13th-seeded Spaniard Tommy Robredo 3-6, 6-2, 7-6 (7-3) and Swede Robin Soderling erased 14th-seeded Australian Open runner-up Jo- Wilfried Tsonga of France 6-2, 7-5. Robredo titled here two years ago.

In other second-round action involving seeds, No. 11 Spaniard Carlos Moya beat Belgian lucky-loser Olivier Rochus 7-5, 6-3, No. 12 Argentine Juan Monaco mauled Italian Simone Bolelli 6-2, 6-1 and No. 15 Brit Andy Murray doused Frenchman Gilles Simon 6-3, 6-3.

Additionally, German crowd favorite Nicolas Kiefer downed last week's Italian Masters runner-up Stanislas Wawrinka 7-5, 7-5 and Spaniard Albert Montanes dismissed Argentine Jose Acasuso 7-6 (7-3), 6-3. The Swiss Wawrinka, who lost to Serbian star Novak Djokovic in last week's finale in Rome, entered the draw here as the 10th-ranked player in the world.