catherine bellis

Marin Cilic of Croatia celebrates with the U.S. Open trophy after defeating Kei Nishikori of Japan in the men's singles final on Monday in New York...

Catherine "CiCi" Bellis won the 2014 edition of Costa Rica's junior circuit tournament known as the Copa del Café. After her victory, the 14-year-old admitted to feeling nervous at the start because of all the spectators watching. Tonight, Bellis, who turned 15 in April, could have an audience in the millions.

Catherine Bellis, who won Costa Rica's Copa del Café in January, is the youngest girl to win a match at the U.S. Open since Anna Kournikova did it in 1996.