Turbos hooker Siua Maile scored two tries in the opening eight minutes - finishing off a close range lineout drive, then running an intercepted pass 70 metres to the tryline.
Manawatū's defence has been suspect this season, and the first time the Magpies got some ball in enemy territory, they struck back.
First five eighths Lincoln McClutchie made a half break and offloaded to get Hawke's Bay in behind, and Brad Weber finished the try in the 14th minute.
Magpies prop Pouri Rakete-Stones was caught for side entry at a ruck, allowing Brett Cameron to extend the Turbos lead to 10 with a penalty goal.
Hawke's Bay punched straight back in the 22nd minute with Weber's second five-pointer.
The halfback's midfield box kick fell to the ground allowing him to regather, put another kick in behind, and slide over the tryline with the ball in the heavy rain.
Cameron hit the post with another penalty attempt, but Manawatū stopped three straight rolling mauls from Magpies attacking lineouts to keep their lead through 35 minutes.
It was fourth-time-lucky for the Magpies, as substitute winger Lolagi Visinia scored a phase after their maul collapsed just short of the line.
That was Visinia's first touch after replacing Jonah Lowe, who was helped off the field with a nasty ankle injury.
Having taken their first lead just before halftime, the Magpies looked to have shot themselves in the foot in the 48th minute when captain Tom Parsons was caught striking his opposite lock Micaiah Torrence-Read around the head area multiple times.
Parsons was reacting to illegal breakdown play from Torrence-Read, and the referee gave both players yellow cards after an inquest.
Cameron missed the resulting penalty shot that would have given Manawatū the lead.
On leave from All Blacks duty, halfback Folau Fakatava came on for the final 25 minutes and gave the Magpies an immediate spark.
He did spurn an overlap to take the line on himself after an attacking scrum though, resulting in a turnover.
Pouri Rakete-Stones' would-be try in the 61st minute was called back for a forward pass in build-up.
Lincoln McClutchie finally scored a try five minutes later for the first points of the second half.
Substitute hooker Tyrone Thompson scored after 13 phases to put Hawke's Bay more than two scores clear.
Fullback Chase Tiatia scored a drop goal in the 76th minute, and replacement flanker Sam Smith had the final say with the Magpies' sixth try just before fulltime.
Their next game is a Ranfurly Shield defence against North Harbour at McLean Park on Saturday afternoon.
Manawatū 17 (Maile 2 tries; Cameron 2/2 cons, 1/2 pens)
Hawke's Bay 43 (Weber 2, Visinia, McClutchie, Thompson, Smith tries; McClutchie 4/5 cons; Tiatia drop goal)
HT: 17-19