NEW YORK - Five-time winner Roger Federer and defending champion Serena Williams breezed into the US Open third round on Thursday while Italian fourth seed Sara Errani became the biggest upset victim yet.
Swiss 17-time grand slam champion Federer, who swept the New York hardcourt crowns from 2004-2008, dispatched Argentina's 48th-ranked Carlos Berlocq 6-3 6-2 6-1 in 95 minutes, firing six aces and 37 winners.
Federer, at his lowest US Open seeding since 2002 at seventh, advanced to a matchup with US 26th seed Sam Querrey or Frenchman Adrian Mannarino.
Federer lost for the first time in 50 appearances in a grand slam second-round last month at Wimbledon, falling to 116th-rated Sergiy Stakhovsky.
"Just keep on winning. I don't care how," Federer said of his goals. "Right now, it's about winning for me, trying to gain confidence and enjoy myself. I hope I can progress. We'll see how it goes."
Federer and Spanish second seed Rafael Nadal could meet for the first time at the US Open in this year's quarter-finals.
"The biggest mistake I can do is focus on Rafa right now," Federer said. "Clearly I would love a match with Rafa."
Nadal, unbeaten on hardcourts this year and favourite to claim the crown, will make his bid for a place in the third round against Brazilian qualifier Rogerio Dutra Silva.