No. 1-seeded Novak Djokovic advanced when first-round opponent Conor Niland was forced to retire from the 2011 U.S. Open with an illness. At the time of Niland's retirement, Djokovic was leading 6-0, 5-1 and had been on the court just 44 minutes.
Niland apparently got food poisoning the night before and got sick on the court during warmups. In his first U.S. Open match, he did not look comfortable at Arthur Ashe Stadium. Niland had made 18 unforced errors and two double-faults, as opposed to one ace and just three winners.
Djokovic, who was forced to retire because of a shoulder injury in Cincinnati, did not seem particularly concerned. He needed just 21 minutes to win the first set, after which Niland asked for assistance from the trainer. He held his serve to open the second set, but that proved to be his only highlight.
In other afternoon results on the men's side, No. 14 seed Stanislas Wawrinka survived losing the first set to advance and No. 17 seed Jurgen Melzer won in straight sets.