Errani, who finished second at this year's French Open and won the Italiacom Open in 2008, will go against Romanian Alexandra Cadantu in the quarterfinals on the red clay at Country Time Club.
Cadantu bounced seventh-seeded Frenchwoman Alize Cornet 6-3, 5-7, 6-2 to gain the quarterfinals.
In other second-round action, Romanian Irina-Camelia Begu defeated Spaniard Lourdes Dominguez Lino 3-6, 6-1, 6-4 and Spanish qualifier Estrella Cabeza Candela downed Italian wild card Maria Elena Camerin 7-6 (7-3), 7-5. Begu will go against Cabeza Candela in Friday's quarterfinals.
In a final opening-round match, eighth-seeded Czech Barbora Zahlavova Strycova eliminated Spaniard Silvia Soler-Espinosa 7-5, 7-6 (7-3). The match had been suspended because of darkness Tuesday.