Spain's Rafael Nadal advanced to the third round of the US Open on Friday after outclassing German veteran Nicolas Kiefer 6-0, 3-6, 6-3, 6-4.

World number two Andy Murray also reached the top 32 with a four-set victory. The 22-year-old Scott defeated Chile's Paul Capdeville 6-2, 3-6, 6-0, 6-2.

"I played three very good sets and one poor one, but you're allowed to play a bad set sometimes," Murray said. "I came back well from it."

Argentine number six Juan Del Potro dispatched Austrian Jurgen Melzer 7-6 (8-6), 6-3, 6-3, firing 13 aces and 36 winners to advance to his fifth victory without a defeat against the number 38.

Seventh seed Jo-Wilfried Tsonga cut short the wrist injury comeback of Jarkko Nieminen as he defeated the Finn 7-5, 6-3, 6-4.

The 2008 Australian Open finalist next faces fellow Frenchman Julien Benneteau, who beat Serb Viktor Troicki 6-1, 3-6, 6-1, 6-0.

Two other French seeds joined Tsonga with number nine Gilles Simon beating Tomaz Bellucci of Brazil 6-3, 6-2, 6-4 and number 13 Gael Monfils ousting German Andreas Beck 6-3, 7-5, 6-3.

Croatian 16th seed Marin Cilic staged a career-first comeback from two sets to love down, upsetting American player Jesse Levine 4-6, 2-6, 6-0, 6-3, 6-0.

Second-seeded women's holder Serena Williams had to win a lengthy 11th game of the second set lasting seven deuces to overcome Maria Jose Martinez Sanchez 6-3, 7-5.

Sister Venus Williams overcame knee pain, defeating Slovak Magdalena Rybarikova 6-2, 7-5 to next face Kim Clijsters, who continued her impressive comeback to tennis as she routed fellow Belgian Kirsten Flipkens 6-0, 6-2.

Russian Vera Zvonareva beat compatriot Elena Vesnina 6-2, 6-4 while veteran Italian Francesca Schiavone upset eighth seed Victoria Azarenka 4-6, 6-2, 6-2.

Tenth seed Flavia Pennetta of Italy crushed Canada's Aleksandra Wozniak 6-1, 6-1.

(Xinhua News Agency September 5, 2009)