NEW YORK — Maria Sharapova’s serve and her groundstrokes were abandoning her. What she had was her conditioning.The five-time major champion rallied from a set down to beat 95th-ranked Alexandra Dulgheru 4-6, 6-3, 6-2 in the second round of the U.S. Open on Wednesday. Sharapova overcame nine double-faults and 46 unforced errors to improve her record in three-set matches this year to 17-6.Dulgheru had played just twice since mid-July, and she was dragging as the match approached two hours late in the second set.On a hot, windy day, with the shadows shifting as late afternoon turned to evening, the fifth-seeded Sharapova avoided another upset on the women’s side.