Vinci was last year's runner-up at the tournament, which serves as a warm-up for the French Open. She led an exit of four other seeded players, including No. 2 Laura Siegemund, who lost to Mariana Duque-Marino 7-6 (6), 3-6, 6-1.
Fifth-seeded Sabine Lisicki had six double-faults and was also eliminated, losing to Varvara Lepchenko 6-2, 7-6 (5).
Irina Falconi beat sixth-seeded Misaki Doi 6-3, 5-7, 6-4, while Julia Goerges defeated eighth-seeded Yulia Putintseva 6-4, 6-2.