U.S. tennis player Taylor Townsend scored a major victory at the French Open Wednesday, defeating France's top-ranked player, the No. 20 player in the world, Alize Cornet, to advance to the third round in her very first Grand Slam tournament.

"I was doing my little victory dance I was so happy," Townsend, 18, said after her 6-4, 4-6, 6-4, victory. "But it feels really great."

"These are just the moments that I have been working for," she said.

The Chicago-born Townsend began working especially hard, she said, after facing criticism in 2012 from the United States Tennis Association (USTA).

The organization tried to bench Townsend, at the time the top-ranked junior's girl player in the world, for what it said were health reasons. After she won the Australian Open junior title in 2012, the USTA wanted to keep her out of the U.S. Open junior championship later that year because of her lack of physical conditioning.

Many believed that the USTA's language was actually code for saying Townsend was overweight.

"I started working really hard trying to get in the best shape that I could be for my body," Townsend said. "It actually turned out to be a huge strength for me."

That focus on her body, Townsend said, helped her become a stronger player both physically and mentally.

"It helped me believe in myself more," she said. "It also opened my eyes to say, 'You know, you're not going to look like everyone else."

Townsend, the youngest American woman to reach the third round of the French Open since 2003, will face Spain's Carla Suarez Navarro in the third round. The match is expected to be played Friday.