Drysdale backed up his batting heroics holding two catches in the deep, as Cadets were dismissed for 134, to give Mount Maunganui their first Baywide T20 title.
Mount captain Dale Swan bowled his usual economic style to capture three wickets, while Chris Atkinson took three wickets as well. Craig Baldry, fresh out of Tauranga Boys' College, took two wickets for his new club.
The Mount Maunganui victory reversed a six-wicket Cadets win in preliminary play the previous weekend.
While Cadets had already booked a finals berth, with enough points, while sitting out the early afternoon round seven bye - Mount Maunganui qualified for the decider after beating Te Puke in the last qualifying round.
Mount Maunganui batted first and posted 163/8. Ben Musgrave top scored with 31 runs. New Te Puke recruit Mikaere Leef took two wickets.
Led by a half century from veteran Tai Bridgman-Raison, Te Puke were in the hunt for victory throughout most of the contest.
However, they were restricted to 146/9 to give Mount Maunganui a place in the final.
In other round seven action, Greerton beat Central Indians and Lake Taupo finished at the bottom of the points table after being defeated by Tauranga Boys' College.
Bay of Plenty Cricket Results - January 20
Twenty20 final:
Carrus Mount Maunganui 176/6 (P Drysdale 92, N Smith 38; S Davey 3-31, J Boult 2-29) beat Element IMF Cadets 134 (S Davey 42; D Swan 3-12, C Atkinson 3/33, C Baldry 2-21)
Round Seven:
Carrus Mount Maunganui 163/8 (B Musgrave 31, D Smith 27, N Smith 25; M Leef 2-30) beat New World Te Puke 146/9 (T Bridgman-Raison 58, C MacDonald 26no; D Smith 2-22)
Eves Realty Greerton 146/7 (T MacRury 46) beat Bayleys Central Indians 102.
Cooney Lees Morgan Tauranga Boys' College 163/5 (I Singh 47, T Clarke 41, M Collett 35) beat GM Painters Lake Taupo CC (score not supplied).
Element IMF Cadets the bye.
Final points
Cadets 15, Mount Maunganui 15, Greerton12, Te Puke 9, Central Indians 6, Tauranga Boys College 6, Lake Taupo CC 0