Ireland 294 for 7 (Doheny 84, Tector 75, Chatara 3-51, Evans 2-66) beat Zimbabwe 248 (Ballance 52, Kaia 51, Burl 41, Little 4-38) by 46 runs
Harare: Josh Little took career-best one-day international figures of 4-38 as Ireland squared the series with Zimbabwe with a 46-run win in Harare.
The tourists posted 294-7 from their 50 overs with Stephen Doheny hitting 84 while Harry Tector added 75.
Zimbabwe reached 207-4 before the wickets tumbled and fell well short of the target on 248 all out.
Paceman Little was in top form as Ireland made it 1-1 after a three-wicket defeat in the opener.
Ireland went into the second ODI without captain Andrew Balbirnie, who was ruled out for the remainder of the series after retiring in Wednesday's game with concussion.
Doheny, who made his maiden international half-century, and Paul Stirling (45) put the Irish on course for a healthy total with a 104-run partnership for the opening wicket after Zimbabwe elected to bowl first.
It was also a memorable day for Tector - coming in four runs short of 1,000 ODI runs, it took just eight balls for the 23-year-old Dubliner to break the Irish record as the fastest Ireland men's player to reach the milestone, taking just 25 innings to do so.
George Dockrell contributed a valuable 35 while Tendai Charata was the pick of the home bowlers with 3-51.
Zimbabwe opener Tadiwanashe Marumani was dismissed by Little with just one run on the board before Innocent Kaia (51) and Chamu Chibhabha (40) took the hosts to 90-1.
Gary Ballance (52) and Ryan Burl (41) guided Zimbabwe to a strong position before the Ireland attack took control to secure victory with 15 balls to spare.
The sides will meet again in the decider at Harare Sports Ground on Monday.