Roberta Vinci wins 1st Palermo title
The second-seeded Vinci was broken in the first game, but she broke back twice before serving out the opening set.
Errani, who won this tournament in 2008 and 2012, raced into a 5-1 lead in the second set.
But Vinci went ahead 4-0 in the final set and then held off the sixth-ranked Errani's comeback attempt to secure her ninth career victory.
The win also ends a streak of five straight victories for Errani over her close friend and doubles partner.