Ed Rainsford hit the final ball of the match for six to seal Zimbabwe's two-wicket victory over Ireland in the first one-day international.
Tatenda Taibu hit 62 off 106 balls to provide the groundwork for the hosts' pursuit of a target of 201 at the Harare Sports Club.
But Taibu's departure, caught by Paul Stirling off Trent Johnston's bowling, reduced Zimbabwe to 125-5 in the 37th over.
Skipper Elton Chigumbura blasted 41 from 32 deliveries to take Zimbabwe to the brink of victory but was Johnston's (2-36) second victim with seven still needed from the final seven balls.
Ninth-wicket pair Graeme Cremer (6no) and Rainsford (9no) managed to bring the scores level with one delivery left - and medium pacer Kevin O'Brien (1-61) delivered a full toss which Rainsford promptly dispatched over the rope at long-leg.
Earlier, Ireland had been bowled out for 200 in 47.3 overs after being asked to bat.
Rainsford struck three times in his opening spell as the tourists slumped to 22-4 before a fifth-wicket stand of 115 between Andrew White (47) and Gary Wilson (69) briefly revived their fortunes.
But Wilson's dismissal sparked another collapse, Ireland leaving 15 balls of their innings unused as Rainsford finished with one-day best figures of 4-23.
The three-match series continues at the same venue on September 28.