The second half was about Manawatu finding a way to protect their lead, which they managed to do via a try to Nathan Tudreu.
Despite the win, Manawatu coach Jason O'Halloran, who sets high standards for his men, may have been concerned with their ball security, which wasn't where it should have been.
Two late Bay of Plenty tries brought them within inches of a thrilling comeback and despite suffering another defeat, they did manage to salvage two bonus points. The victory catapulted Manawatu to the top of the Championship division.
Bay of Plenty will have a chance to finally get a win under their belts when they host North Harbour - who are also yet to post a win this year - in Rotorua on Sunday.
Manawatu will continue their promising campaign with a home outing against Counties Manukau on Sunday.
BOP's demise: After being relegated last year, the wheels have fallen off for Bay of Plenty. They've dropped their first four games of the 2014 campaign and need to change things quickly.
Close call: Manawatu have a habit of putting their fans through turmoil during the final stages and they did the same again here as they nearly coughed up a 14-point lead.
Manawatu 29 (Nathan Tudreu, Antonio Kiri Kiri, Newton Tudreu tries; Otere Black 4 pen, con)
Bay of Plenty 27 (Siegfried Fishiihoi, Culum Retallick, Mike Kainga, Joe Royal tries; Dan Hollinshead con, Byron McGuigan pen, Te Aihe Toma con)
Halftime: 21-12.