Capriati, 28, beat 16-year-old Frenchwoman Tatiana Golovin 6-3, 6-2, after receiving a bye into the round of 16.
Capriati beat Lindsay Davenport in last year's all-American final here.
In other second-round play, seventh-seeded Russian Elena Bovina defeated Spaniard Marta Marrero 6-3, 6-2. In opening-round action, Slovakian Daniela Hantuchova beat American Lindsay Lee-Waters 7-6 (7-2), 7-5.
Top-seeded Davenport pulled out on Monday, leaving American lucky-loser Marissa Irvin to take her place in the draw. Hantuchova will face Irvin, and not Davenport, in the second round.
Davenport, who pulled out with a wrist injury, has won her last four tournaments.