Despite the high winds, Manawatu had batted well all week and made a good start in the final with Sean Mongahan scoring 43.
However, NH Black's bowlers tightened their line and bowled at the stumps, which they hit several times as Manawatu fell to 99-6 before eventually being all out in the last over for 132. Ryan Jenner took 4-20 from his five overs.
The momentum swing continued during NH Black's reply as impressive Manawatu bowling reduced them to 18-3 and then 69-5 as Reuben Love got both the openers among his 3-24 from five overs.
However, NH Black's tailenders came firing back, with Riley Mudford making 30 before being run out.
Manawatu spinner Jack Wenham got the dangermen to finish with 3-14 from five overs as NH Black were all out for 118.
Across the park, both the Wanganui teams enjoyed wins on the final day.
Blue had a comfortable eight-wicket victory over NH Burgundy, as Cameron Macintosh made an unbeaten 55 in their innings of 142-2 in reply to the North Harbour team's 140-6.
White finished their tournament with a four-wicket thriller over Horowhenua-Kapiti, earning the winning runs with four balls to spare. Having bowled Horowhenua-Kapiti out for 142 in the 27th over, with Joel Clark taking 3-25 off four overs, White needed eight runs off the final 12 balls. They got them through very good running between the wickets on byes and overthrows, although Horowhenua-Kapiti did drop a crucial catch when five runs were needed.
Henry Deans (33), Sam Sherriff (29) and a great hand at the death by Levi Woolston (28 not out) saw White home.
The Festival continues today with the start of the under-12 (Year 7) tournament. Wanganui, South Taranaki, Manawatu and Auckland Parnell will play each other in 35-over and Twenty20 formats.
The first games will begin at 1pm today and the final matches will be on Tuesday.