Orla Prendergast cleared the ropes from the penultimate ball of the match to hand her side a nine-wicket win in a rain-curtailed eight-overs match in Harare.
Needing two to win, the Pembroke all-rounder ensured there wouldn't be another tied match between the sides, with a match winning unbeaten 27 from 17 balls as they chased down their 66 target.
She and Gaby Lewis (20*) shared a second wicket stand of 36, after Lewis and Hunter (19) benefitted from the hapless Zimbabwean fielding to get Ireland on their way in an opening partnership of 34.
Ireland had also been far from their best in the field, with the damp conditions obviously affecting both teams.
Georgina Dempsey got the prize scalp of home skipper Mary-Anne Musonda in the first over, although Zimbabwe went on to score at over eight an over - ending on 65 for 5.
The series concludes on Friday with another contest under floodlights, when a dominant Ireland will look to complete a whitewash at the Harare Sports Club.