Errani, this year's French Open runner-up, won the Sicily event in 2008 and settled for second place the following year.
She put herself in position for another victory with her quick 6-4, 6-1 semifinal decision over Irina-Camelia Begu of Romania, which took just 76 minutes to complete.
Eighth-seeded Zahlavova Strycova, meanwhile, rallied for a 2-6, 7-5, 6-2 victory over Briton Laura Robson in Saturday's other semifinal.
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