Zimbabwe were bowled out for 128 in 37 overs after Pakistan had piled up 259 for six. A century partnership from Mohammad Rizwan and Imad Wasim set the touring side up for victory but it was the leg breaks of 29-year-old spinner Yasir that proved decisive.
Imad and Rizwan shared a stand of 124 for the sixth wicket to help Pakistan recover after they had slumped to 35 for three.
Rizwan scored a career-best 75 not out and Imad, run out for 61, struck a maiden international half-century.
Zimbabwe then lost wickets at regular intervals in their reply.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Sean Williams top-scored with 26 as Yasir returned his best ODI figures and off-spinner Shoaib Malik claimed three for 30.
The second game in the three-match series, all being played at the Harare Sports Club, is on Saturday.
(Reporting by Mark Gleeson; Editing by Tony Jimenez; mark.gleeson@thomsonreuters.com; +27828257807; Reuters Messaging: Reuters Messaging: mark.gleeson.thomsonreuters.com@reuters.net)
