Cibulkova routed Sorana Cirstea of Romania 6-1, 6-1, while seventh-seeded Italian Errani was a 6-1, 6-2 winner over Spain's Carla Suarez Navarro.
Errani's ninth straight victory on clay put her into a second final of the season. The 33rd-ranked Italian looks to follow up her Acapulco triumph in February.
The match Sunday will be third-seeded Cibulkova's first final of the year. The 17th-ranked Slovak has won four of their six meetings -- including the last two. She lost their only meeting on clay in 2007.