Catherine Bellis turned 15 years old in April and sits at 1,208 on the WTA's rankings. At the start of the day, her career record as a pro in singles matches was 8-4. That record has improved to 9-4, as Bellis just finished off 12-seeded Dominka Cibulkova in a first-round match at the U.S. Open.

Bellis took down Cibulkova 6-1, 4-6, 6-4 to become the youngest girl to win a U.S. Open match since 1996, when Anna Kournikova pulled off the feat at the same age. Bellis earned her way into the tournament by winning the girls' 18s national championships earlier this year. She's the youngest girl to win that tournament since a 15-year-old Lindsey Davenport did it in 1991.

You may now commence getting excited about the future of American women's tennis while simultaneously becoming filled with self-doubt over the fact that someone who was born in 1999 had already accomplished much more than you ever will.