The result also guarantees Taranaki a home semi-final in the Mitre10 Cup premiership division with a five point lead over second placed Canterbury.
The shield holders scored four tries in the first half to lead 27-6 at half-time.
After a tight opening 15 minutes of play, Taranaki began to dominate up front from the 20 minute mark, with both ball in hand and territory.
Manawatu meanwhile couldn’t gain any momentum on attack while their defence struggled to cope with speed with the ball.
The visitors’ situation wasn’t helped when tighthead prop Michael Ala’alatoa was sent to the bin for 10 minutes for infringing at the breakdown in the 30th minute.
While Ala’alatoa was in the bin Taranaki centre Seta Tamanivalu scored a double, while All Blacks wing Waisake Naholo scored right on half-time.
After the break, early momentum swung the way of Manawatu and the challengers took full advantage, scoring five points within the first 10 minutes of the second half.
The two sides then scored a try each in the following 15 minutes as Manawatu began to put some solid phases together. However, the damage from the first half meant they were always one step behind.
When all hope appeared lost for Manawatu, a yellow card to Taranaki’s replacement back Declan O’Donnell kept the door slightly open for the challengers.
O’Donnell was shown yellow after a no arms tackle just five metres from his side’s own tryline.
Manawatu took advantage of the overlap and scored a try in the 74th minute to narrow Taranaki’s lead to just nine points.
However the home side wasn’t done, scoring two tries in the final five minutes, pushing their lead out to 21 points.
The Log o’ Wood will stay in Taranaki now for the summer with the side’s final game of the season against North Harbour at QBE Stadium on Sunday.
Manawatu, meanwhile, remain fourth in the championship standings and have their final game of the season also on Sunday, against Hawke’s Bay, where a win should keep them in the top four.