World number one Novak Djokovic received a free pass into the third round of the U.S. Open when Jiri Vesely of the Czech Republic withdrew from their match on Wednesday due to a left forearm injury.
The walkover provided the top-seeded defending champion with an extended break to improve his niggling left wrist injury before his next match against either Guido Pella of Argentina or Mikhail Youzhny of Russia.
The 23-year-old Vesely, ranked 49th, beat Djokovic in the second round at the ATP Masters 1000 Monte Carlo event in April in their only meeting, making him one of two top 100 players with more wins than losses against the Serbian.
World number 23 Ivo Karlovic is 2-1 head-to-head against Djokovic.
Meanwhile, South African ace Kevin Anderson advanced into the next round by scraping past Vasek Pospisil of Canada 7-6(3) 6-4 6-4.
Vinci, Cibulkova & Kvitova advance
Seventh seed Roberta Vinci will not catch anyone by surprise with a run to the U.S. Open final like she did a year ago but the Italian continued to raise eyebrows on Wednesday with a speedy win over Christina McHale.
Pennetta, who was unseeded last year when she lost in the final to compatriot Flavia Pennetta, has offered early signs that a return trip could be in the offing as she raced into the third round with a 6-1 6-3 win over American McHale.
The straight-forward victory, which Vinci wrapped up in 63 minutes, followed a clinical first round win over Germany's Anna-Lena Friedsam that took 68 minutes.
Vinci, 33, will next face either Kazakhstan's Yulia Putintseva or Germany's Carina Witthoeft.
Dominika Cibulkova of Slovakia fought through a heavily taped left hamstring to move on 6-7, 6-2, 6-2 over Evgeniya Rodina of Russia.
Also, Petra Kvitova of Czech Republic edged out Turkey's Cagla Buyukakcay 7-6(2) 6-3.
Switzerland's Belinda Bencic advaced by thrashing Andrea Petkovic of Germany 6-3 6-2.