NEW YORK — Only one man in tennis history has beaten Rafael Nadal and Roger Federer in the same Grand Slam event.It was two years ago that Juan Martin del Potro pulled off that historic double-double to win the 2009 U.S. Open, but for him it feels like it was just yesterday. “When I was walking around the street or when I talk with the fans, they say, I remember your final. You can repeat again. You can win again,” the 18th-seeded del Potro said after he dismantled helpless Italian Filippo Volandri 6-3, 6-1, 6-1 in just 1 hour, 28 minutes inside Louis Armstrong Stadium. The 6-foot-6 Argentinian has now won eight straight Open matches dating to 2009 when he won his only major. He was unable to defend his title here a year ago while he continued to recover from wrist surgery. He was off the tour from January to September 2010. “Has been a really sad year, 2010, for me,” he said. “Just for my wrist problem. It took a long time to fix it and then to come back, but I think that was the past. Completely behind me. I can play the tennis again.” He has made an encouraging comeback this year, winning titles at Delray Beach and Estoril, and reaching three other semifinals. He advanced to the round of 16 at Wimbledon, losing to Nadal. Against Volandri, a clay court specialist who is now the loser of 11 straight hardcourt matches, “Delpo” launched 18 aces among 38 winners and broke Volandri seven times while cranking serves that reached 130 mph. He also made 18 unforced errors on the big flat forehand that helped him topple Nadal and Federer.“I know I have to be more focused in the important moments playing against top 10 players, but, you know, that takes time,” he said. Though the crowd was not especially vocal on Wednesday, he said he remembers how the New York crowd, fueled by a contingent of Argentinians, supported him in the 2009 final when he trailed Federer, then the five-time defending champion, by two sets to one. “I’m really enjoy the crowd, the fans are crazy, and they are very excited,” he said. “Every match, the crowds are full every match.” Up next for del Potro, who is now 14-3 lifetime in New York, will be fellow Argentine Diego Junqueira. Looming ahead is a potential quarterfinal against No. 4 Andy Murray, who advanced to the second round over Somdev Devvarman of India, 7-6 (5), 6-2, 6-3. Del Potro said he’s looking more toward 2012, when he imagines being fully healthy, but he did not dismiss the possibility of “defending” the title he won in 2009 when he made history. “This is tennis,” he said. “Every player can beat anyone, especially in Grand Slam, five-set matches, you know, and two weeks of tournament. “So just be focused, and then if you have the chance or if you see the chance, go to it.” FREE THROWS No. 21 seed Andy Roddick, the 2003 champ, prevailed over fellow American, Michael Russell, in four sets…The top-seeded doubles team of American twins Bob and Mike Bryan was upset by Ivo Karlovic and Frank Moser, 6-4, 2-6, 6-2...Steve Johnson, the reigning NCAA champion from USC, blew a two sets to love lead against fellow American Alex Bogomolov, 4-6, 4-6, 6-3, 7-6 (3), 6-3…On the women’s side, No. 2 Vera Zvonareva advanced in three sets. No. 3 Maria Sharapova moved on in straight sets.