A third-wicket partnership of 137 between in-form opener Martin Guptill and Kane Williamson has carried New Zealand to a seven-wicket victory in the first Twenty20 cricket international in Auckland.

Zimbabwe had produced their most competitive batting effort of a tough tour in posting 8-159 after winning the toss at Eden Park on Saturday night.

In reply, the Black Caps overcame some initial alarms before completing an ultimately comfortable passage to 3-160 with 19 balls to spare.

Guptill, the top scorer in the domestic T20 competition with 504 runs for Auckland at an average of 72, continued his superb summer with an unbeaten 91 off 54 balls.

It was his fifth half-century in five innings against the tourist in all three forms of the game.

He had a let-off on 13 when he survived what looked like a very good lbw shout from Kyle Jarvis.

He then had a life on 20, as Hamilton Masakadza spilled a difficult chance in the deep.

Those wobbles apart, Guptill was in fine touch as he plundered five fours and six sixes.

Williamson provided able assistance with 48 off 24 balls, before he was run out going for a quick single.

Earlier, the Black Caps made a stuttering start as opener Rob Nicol (12) and skipper Brendon McCullum (0) both fell to Jarvis in the second over.

At 2-15, Williamson joined Guptill for the match-winning stand.

Zimbabwe, who had gone into the match after to heavy defeats in the one-off Test and the three one-dayers, showed good spirit to fight back from 16-2 in their own innings.

Opener Hamilton Masakadza and Elton Chigumbura provided the backbone to their batting effort, Masakadza hitting three fours and three sixes in a 36-ball 53.

Chigumbura blazed away at even quicker pace, racking up 48 run off just 24 deliveries and hitting seven boundaries, including four sixes.

Zimbabwe end their tour with the second T20 international in Hamilton on Tuesday night.