Referee Ben O'Keefe required the assistance of TMO Mark Johnson before awarding the Steamers their first try to flanker Shahn Eru in the 23rd minute. Evemy slotted the conversion.
Penalties from Magpies pivot Ihaia West in the 34th and 38th minutes gave the hosts the edge. The first came after Steamers openside flanker Zak Hohneck was sinbinned for offside infringing near the posts.
The Magpies, who scored 13 points while Hohneck was in the bin, drew first blood in the second spell when the forwards displayed better cohesion and flanker Tom Stanley scored as the forwards pushed their way over the line in the 43rd minute. West slotted the conversion.
Fellow flanker Tony Lamborn scored the Magpies third try in the 48th minute to give the hosts a 23-10 lead.
Three minutes later Evemy scored a cracker of a solo try which he converted. With this gap it was a nailbiting finish for the home crowd who were relieved to see the Magpies hang on.
They know vast improvement will be required in the next defence against Premiership outfit Auckland on Thursday night.
Scorers:
Hawke's Bay23 (Ryan Tongia, Tom Stanley, Tony Lamborn tries; Ihaia West 2 pens, con), Bay of Plenty 17 (Shahn Eru, Nick Evemy tries; Evemy 2 cons, pen). HT: 11-10.