American teenager Victoria Duval stunned 2011 U.S. Open champion Sam Stosur in the tournament's first round Tuesday.
The 17-year-old qualifier, ranked 296th, won 5-7, 6-4, 6-4, leaping into the air in celebration after converting her fourth match point with a forehand winner.
Duval was playing in just her second Grand Slam match. She also faced a former U.S. Open champ, Kim Clijsters, in the first round at Flushing Meadows last year.
She was facing a top-20 opponent for the first time Tuesday.
The 11th-seeded Stosur had reached at least the quarterfinals in her last three trips to the U.S. Open. She had 56 unforced errors.
Duval was born in Miami but lived in Haiti until she moved back to the United States at age 8. She trains in Bradenton, Fla.