New York: Serena Williams withstood a "rough and rowdy" challenge from American wildcard Caty McNally, 17, at the US Open on Wednesday to keep her bid for a record-equalling 24th Grand Slam title intact.

Serena, a six-time champion in New York, recovered from dropping the opening set to prevail 5-7, 6-3, 6-1 and set up a third-round showdown with either 29th seed Hsieh Su-Wei or Karolina Muchova.