New York:World number one Rafael Nadal of Spain rolled into the fourth round of the US Open while Japanese teen Kei Nishikori pulled off the biggest upset on a Saturday of shockers that saw three top men ousted.
Wimbledon and French Open champion Nadal raised his game when challenged, winning his final 11 games to answer a fightback and defeat 71st-ranked Serbian Viktor Troicki 6-4, 6-3, 6-0, for his 41st triumph in 42 starts.
"I have started playing better," Nadal said. "Today I served very well. I have more confidence and I hope to continue to improve my tennis. I know I have to keep improving my tennis if I want to win."
Nishikori stunned Spanish fourth seed David Ferrer 6-4, 6-4, 3-6, 2-6, 7-5 to become the first Japanese man into the fourth round of a US Open.
"I'm very proud of that," said Nishikori, who at 18 is the youngest man in the US Open round of 16 since Marat Safin in 1998.
"I still can't believe it. I felt happy and more positive. That's why I felt I could fight through."
Ferrer was joined on the seeded scrap heap by Argentine number seven David Nalbandian, who lost to France's Gael Monfils 6-3, 6-4, 6-2, and US ninth seed James Blake, who fell to compatriot Mardy Fish 6-3, 6-3, 7-6 (7/4).
Ferrer denied Nishikori on a match point in the ninth game and broke back, then saved another match point in the 10th game before Nishikori blasted back-to-back forehand winners to end it after three hours and 32 minutes.
"Nishikori played really well," Ferrer said. "I'm not surprised. I'm sure he will be a very good player."
The only Japanese man to go deeper in a Grand Slam event was Shuzo Matsuoka, who reached the 1995 Wimbledon quarter-finals.
"I don't think about it like I'm making history," Nishikori said. "I'm just very proud."
Next up for the Asian sensation is Argentina's Juan Martin Del Potro, who stretched his win streak to 22 matches by outlasting France's Gilles Simon 6-4, 6-7 (4/7), 6-1, 3-6, 6-3 over three hours and 47 minutes.
British sixth seed Andy Murray barely avoided the victims list, rallying to defeat Austrian Jurgen Melzer 6-7 (5/7), 4-6, 7-6 (7/5), 6-1, 6-3 after three hours and 52 minutes and book a date with Swiss 10th seed Stanislas Wawrinka.
"He was playing unbelievable," Murray said. "I really didn't get any rhythm. I just kept fighting. This is why you put in all the work. Hopefully I can keep it going."
On the women's side, seventh seed Venus Williams and fourth-seeded sister Serena cruised in third-round matches at Arthur Ashe Stadium, moving them one step closer to a quarter-final showdown at the year's last Grand Slam event.
But the men stole the show. Olympic champion Nadal was down a break in the second set until blasting a running forehand winner past Troicki to level at 3-3 and he never lost another game.
"That gave me a lot of confidence that I could win," Nadal said. "He was playing well in that moment but after that I started playing better and he made some mistakes."
Nadal can match his best US Open showing by winning his next match over Sam Querrey, the 55th-ranked American who ousted Croatian 14th seed Ivo Karlovic 7-6 (7/5), 7-6 (7/5), 6-2. Nadal won their only prior meeting in 2006.
"I've gotten a lot better since then. He has too," Querrey said. "I can go out there and rip away. I have nothing to lose."
Nadal, whose only loss since May was to Serbian third seed Novak Djokovic in a Cincinnati semi-final, could join Roger Federer, Rod Laver and Pete Sampras as the only men to win three Slams in a row in the Open era.
Seven-time Slam champion Venus Williams advanced by beating Ukraine's Alona Bondarenko 6-2, 6-1 in 56 minutes. Next up is Polish ninth seed Agnieszka Radwanska, who beat Williams in 2006 at Luxembourg in their only prior meeting.
"I'm looking forward to evening the score," Williams said.
Eight-time Slam champion Serena Williams beat Japan's Ai Sugiyama 6-2, 6-1 and will next face French wild card entrant Severine Bremond, who outlasted Italy's Tathiana Garbin 7-5, 3-6, 6-4.
"I'm definitely not at my best, but I hope to get there," Serena Williams said.
Russian sixth seed Dinara Safina beat Swiss teen Timea Bacsinszky 3-6, 7-5, 6-2 and will next face German Anna-Lena Groenefeld, the first woman qualifier since Anna Kournikova in 1996 to reach the US Open's fourth round.
Sunday's top matches find defending champion Federer playing Czech Radek Stepanek, fellow second seed Jelena Jankovic facing Denmark's Caroline Wozniacki and Australian Open champion Djokovic meeting Croatia's Marin Cilic.