However, coming off twice for short rain delays, United's momentum was stymied and the pitch also moistened as Morgan Inness got two of the dangermen out to catches.
Chris Sharrock was coming off his outstanding century for Active Physio Wanganui but went quickly to a caught and bowled by Sam O'Leary.
Having to regroup, United's Brendon Walker continued his strong form with the bat with another 50, hitting seven boundaries and a six, before being bowled by Craig Thorpe.
United's tail fell victim to representative bowler Sam Beard, until Matthew Simes stuck in for a solid 24 not out, scooping the bat down for a lot of trick shots for hard-run two's to get his team through to a middling 234/8.
Hobbs admitted his team should have had another 40-50 runs to work with after their rapid start, but in the end it didn't matter as Marist's top order floundered to be 27/3.
United's bowling group were all among the wickets as leading hopes John McIlraith, Morgan Inness, Craig Thorpe and O'Leary were all gone after a handful of scoring shots.
There was a little wag in the tail as Stewart (39) and then last man Marcus Howie (22 not out) managed to find the boundary rope by taking on United's spinners, but when Smith hit Thomas Redpath's stumps, Marist had reached only 50 per cent of their target without a tenth wicket available.
Hobbs was still pleased as United's goals for the start of the summer were to win the local knockout competition and the combined Coastal Cup with the Horowhenua-Kapiti club sides.
"We're half way there. We batted okay, wasn't the greatest, and we bowled well."
United will now face the Taranaki one-day champions on January 24 in the next stage of the National Zonal Qualifiers.
In Saturday's playoff for third-fourth on Tasman Tanning No3, Tech were reinforced by the return of some key players and their tail wagged against Saracens, setting up a three wicket win.
Result
United 234/8 (B Walker 50, G Smith 41, M Boswell 27, G Hobbs 27, C Thorpe 2-28, M Inness 2-31, S Beard 2-39) bt Marist 117 (C Stewart 39, M Howie 22no, J Pennefather 2-11, H Kirk 2-20) by 117 runs.