Castellvi, a senior from Guaynabo, Puerto Rico, went 44-8 in singles and 31-15 in doubles play last season, leading UT to its first-ever NCAA Final Four appearance. She became just the second player in Lady Vol history to reach the NCAA quarterfinals and finished the year ranked No. 4 nationally. She and Agnes Wiski ranked 15th nationally as a doubles tandem. Wiski has since graduated, so Castellvi is scheduled to pair with freshman Melissa Schaub in doubles this season.
Castellvi was named Lady Vol "Athlete of the Year'' in June. She won her first singles title on the USTA Professional Circuit in August, claiming the Rockingham Heritage Bank/USTA Women's Professional tourney hosted by James Madison University.