Reducing Marton to 50-7, United's opening bowlers Tomasin Connor (3-14) and Tevita Taumoeanga (2-20) had done the damage, being well supported around the park.
Kenny said sometimes Premier 2 players can have their concentration or skill levels waver, as happened at the end of last year's final, but this time everyone stayed focused.
"It was our best fielding effort in the last 3-4 years. We didn't drop a catch.
"Karl [Bremmer] had it under control."
Marton wicketkeeper Chris Rayner (28) staged a late rally, with his best support being Jamie Simmons (14).
In reply, Small would make his 33 off 28 balls with five boundaries, although there was some nervous moments when Keightly Watson, Martin Pennefather and Reuben Janes were dismissed in single figures and Kenny himself went at 85-6.
Captain Bremmer and Daniel Holly snaffled the last seven runs in the space of nine deliveries.
Marton's leading T20 bowler Bryant Galpin had another good afternoon with his spinners, taking 3-19, while captain Dan Ford had 2-11 from his four overs.
This concluded another successful T20 combined grade and Kenny said although there has been talk of changing the draw around so current representative players can take part, they would like to see the current format retained as a more overall competitive division.
"Definitely. We've made the final for three years. Everyone's kind of up for it and it's good to give the young guys something.
"You talk to guys like Tevita and they say they feel more confident about going up to Premier 1."
Scoreboard
Marton 91-9 (C Rayner 28, S Lambert 14, J Simmons 14, T Connor 3-14, T Taumoeanga 2-20) lost to United 2nd IX 92-7 (Z Small 33, A Kenny 26, B Galpin 3-19, D Ford 2-11) by three wickets.