All of the Marist bowlers copped a little stick, with one Andy Manoussos over of spin going for 29 runs.
Sam Beard (3-28) and Zak O'Keefe (2-35) managed to get the players around Lance.
Three of the United batsmen still fell in single figures without being able to get going quickly off around an over's worth of balls each, meaning Lance had just one delivery less than he needed to bring up the triple figures.
Raponi Tofa did well to keep underneath a run rate of six from his maximum four overs (0-23).
In reply, Marist were never really in the chase and batted out to 139-7, which would have been a decent score on another day of club Twenty20.
Hamish Harding (38 from 38) and Beard (55 from 48) put on a 94-run partnership for the second wicket, but that took them through to the 15th over, still needing 93 runs from 31 balls when Harding was dismissed.
Beard went in the next over for 107-3, and then a wicket fell in each over until the finish.
Five of the six United bowlers picked up wickets, with the Gerard Hobbs (2-5) and Andre Canderle (2-24) getting a pair off their two overs each, the latter after he had copped a little stick.
In the other game, Whanganui Collegiate 1st XI picked up a seven wicket victory over Tech Old Boys on the school's No 3 field, winning with four and a half overs to spare.
Having five players away on Furlong Cup duty, Tech were restricted to 116-8, having brought in Taihape's Ritchie Iorns, who top scored with 39, with the next best scores being from the Czerwonka's in Peter (20) and Tim (17).
Collegiate's Adam Beard took 3-19 from his maximum four overs, while Shaun O'Leary had 2-9 from three.
In reply, opener O'Leary completed a good day with an unbeaten 64 from 53 balls, while Beau Hourigan made his comeback from a broken foot to score 31 off 25.
Trent Hemi, Tim Roebuck, and coach Chris Friedel took one wicket each for Tech.
The next round of the Twenty20 competition will be on November 16.
Scoreboards
United 190-5 (T Lance 99no, S Badger 29, T Bidois 28; S Beard 3-28, Z O'Keefe 2-35) bt Marist 139-7 (S Beard 55, H Harding 38, B Icy 24; G Hobbs 2-5, A Canderle 2-24) by 51 runs.
Tech Old Boys 116-8 (R Iorns 39, P Czerwonka 20; A Beard 3-19, S O'Leary 2-9) lost to Collegiate 1st XI 118-3 (S O'Leary 63no, B Hourigan 31) by seven wickets.