American Taylor Townsend handed an upset defeat to Wimbledon champion Simona Halep of Romania, the fourth seed, in the second round of the U.S. Open tennis tournament Thursday. Halep took the first round 6-2, but Townsend came back to win the next two sets 6-3, 7-6.

In the final set, Halep was at match point but Townsend came back to win the set and force a tie breaker. Townsend then took the tie breaker 7-5.

Townsend, a 116th-ranked American who hasn’t always lived up to expectations, took a big step toward turning that around by employing an aggressive serve and volley, chip-and-charge game that’s a rarity on the baseline-centric women’s tour.Townsend moved in against the Wimbledon champion at every chance. She came to the net 106 times, 64 in the deciding set alone, and it paid off, winning 60 percent of those points. By contrast, Halep came forward just 10 times.

Fittingly, Townsend served and volleyed on match point, snapping a sharp forehand volley to Halep’s backhand that she put into the net.

Next up for Townsend is Sorana Cirstea, who won in straight sets earlier over Aliona Bolsova.

Halep defeated Townsend at the French Open earlier this year in just two sets, 6-3, 6-1.