Errani converted four of her 12 break opportunities in defeating Vinci 6-4, 6-2. She took just less than half (36-of-73) of the points off Vinci's serve while saving four of the five break points she saw on the day.
Errani and Vinci, ranked No. 1 in the world as a doubles team, will look to defend their 2013 Australian Open women's doubles title when the year's first tennis major begins next week.
Madison Keys posted the first upset in Sydney, taking out seventh-seeded Simona Halep 6-1, 6-4. Keys had Halep on the defensive throughout the match, winning four of her eight first-set break chances and three of the four she had in the second set.
Wild-card entrant Ajla Tomljanovic ousted Daniela Hantuchova 6-4, 7-5 in Sunday's other main-draw pairing. Tomljanovic had seven aces and won two-thirds of the points on serve.
World No. 5-ranked Agnieszka Radwanska is the top seed and defending champion at the Apia International, one of two final WTA warm-ups before the Australian Open. She and Errani, No. 7 in the world singles rankings, are two of six Top 10 players in the tournament.