World number five Ivan Ljubicic of Croatia and former French Open champion Gaston Gaudio of Argentina were the biggest casualties in second-round matches at the Hamburg Masters on Wednesday.
Third seed Ljubicic, the highest seed left in the draw, was thrashed 6-2 6-0 by Argentina's Jose Acasuso while Gaudio, the number six seed, lost 6-4, 3-6, 6-4 to Frenchman Gilles Simon.
German Nicolas Kiefer, ranked nine for the tournament, was the only other seed to fall on the red clay at the Am Rothenbaum, disappointing the home fans on centre court by losing 6-2, 6-2 to the towering Max Mirnyi of Belarus.
Number four seed Nikolay Davydenko of Russia strolled into the third round, beating Italy's Andreas Seppi 6-1, 6-2 to set up a clash with Finland's Jarkko Nieminen.
Gaudio, who won at Roland Garros in 2004, looked to be in a strong position at 3-0 up in the final set, but the 21-year-old Simon fought back and will play Mirnyi in the next round.
Ukrainian-born Davydenko, a semi-finalist here and at the French Open in 2005, was forced to retire from his third-round match in Rome last week with a leg injury.
But he came through easily on Wednesday against the tall Italian Seppi and is on course to meet fifth-seeded American James Blake in the quarter-finals.
Blake saw off British teenager Andy Murray on Wednesday, winning 6-3, 6-3.
The tournament has its weakest field in years after the world's top two players and the top two seeds, Roland Garros champion Nadal and last year's Hamburg winner Roger Federer, pulled out due to fatigue.
Argentina's David Nalbandian, Andy Roddick of the U.S. and Australia's Lleyton Hewitt had already withdrawn and only five of the world's top 10 started the event.
