At the ITF Women's Circuit , Bellis won the doubles competition in Orlando in 2014 . At the French Open she was in the junior double finals that same year, which she lost with her partner Markéta Vondroušová . Bellis received a wild card for the US Open by winning the USTA U18 championship ; thus she played for the first time in the main field of a Grand Slam tournament . In the first round she defeated the number 12 seeded Australian Open finalist Dominika Cibulková 6: 1, 4: 6 and 6: 4. She was the youngest player since Anna Kurnikowa in 1996 to win a match in the main round of the US Open. In the second round she was defeated by Sarina Dijas 3: 6, 6: 0 and 2: 6. She did not accept her prize money of around 60,000 US dollars in order to continue to compete in college tennis . At the end of September she won the Junior Fed Cup with the US team.
Bellis celebrated her greatest success to date with the final victory at the $ 100,000 Dow Corning Tennis Classic 2016 , where she won the doubles competition with her partner Ingrid Neel . At the US Open in 2016, she reached the main field in the women's singles with victories over Lina Gjorcheska , Grace Min and Alison Van Uytvanck in the qualification . After victories over Viktorija Golubic and Shelby Rogers , she was in the third round, in which she had no chance against Angelique Kerber at 1: 6, 1: 6. In September 2016 Bellis announced that she was aiming for a professional career due to the good results in the current year. After three tournament victories in a row, the last at the Hawaii Open 2016 , a tournament of the WTA Challenger Series , she climbed to 75th place in the world rankings by the end of November. She achieved her best ranking to date in August 2017 with 35th place.