New Zealand had already claimed the T20I series with an unassailable 2-0 lead but Pakistan avoided a clean sweep with victory in the third match in Napier, chasing down the target of 174.
The Black Caps posted 7-173 after stumbling early, with Devon Conway fighting hard to help them beyond 150 with 63 from 45 balls, while Faheem Ashraf impressed with 3-20 from four overs.
In reply, the tourists were held together by Rizwan who made 89 from 59 balls, including 10 fours and three sixes, only losing his wicket in the final over with victory in sight.
Rizwan combined with Mohammad Hafeez (41 from 29) for a critical second wicket stand worth 72 runs to set up the win and offer some momentum to Pakistan ahead of the Tests which begin on Saturday, without captain Babar Azam, meaning Rizwan will lead them again.
“This win is good, we lost the series, but this game was important ahead of the Tests, wanted to take some momentum going into it,” Rizwan said.
“It’s a big honour for me to captain Pakistan. It’s a big deal to play for the country, can’t express my happiness at being captain.
“The management has trusted me a lot, this was the first time I opened in internationals, I have done so in domestic cricket, but I knew I had it in me to perform and was well backed by the management.
“This win is for our supporters, they have backed us a lot.”
Black Caps wicketkeeper-batsman Tim Seifert was named Player of the Series for his run scoring.
New Zealand named a 13-man squad for the First Test on Tuesday, with Mitch Santner added in for Ajaz Patel despite his recovery from a calf issue.