Kerber, a two-time Grand Slam semifinalist, matched her best showing at Key Biscayne by reaching the third round.
On the men's side, Americans Jack Sock and Ryan Harrison won first-round matches. Sock, a qualifier, beat wild card Guido Pella 6-3, 6-4. Harrison, a wild card, defeated Federico Delbonis 6-2, 6-4.
Six-time champion Serena Williams and Maria Sharapova were scheduled to play their opening matches later Thursday. Seeded men begin play on Friday.