Trey Bidois (25) and James Wilson (34) were Clare's main supports, until the allrounder finally fell at 241-6 in the 36th over after swinging one too many times and being bowled by Hadleigh O'Leary (4-28).
Not surprisingly, Marton's innings folded five overs later with only 12 more runs on the board, as O'Leary and Fraser Kinnerley (2-11) cleaned up the youngsters in the tail.
Clare's innings was the second highest in the entire competition, behind only the extraordinary knock by Levin's Jamie Pinfold, who bashed 172 in 109 balls against Marton on January 6.
In reply, Tech scored runs but also lost wickets doing it to be 50-3 in the 12th over, with spinner Bryant Galpin (2-25) getting top order scalps.
After Sam Roebuck (19) got a start, James Dorgan (36) and O'Leary (29) looked to consolidate the innings – carrying Tech through to 122 before Bidois (2-33) recovered from giving away several extras to have Dorgan caught out and then O'Leary the same at 154-6 in the 29th over.
Marton offering up 30 runs in wides among their 41 extras was helping keep Tech in the match.
Ultimately, the clouds settled overhead and the rain which dominated the rest of the weekend was there to stay.
Down at the Wereroa Domain, Marist completed a very strong finish to the Coastal Challenge Cup with a comfortable 72 run win over the home side after their two key representative batsmen delivered and the bowlers put together a strong collective effort.
After a rough start to the competition, Marist won their last four played 50-over games, with a rain abandoned match in the middle of the run against champions Paraparaumu ultimately costing them an outside chance at the semifinals.
Marist raised 258 by the 48th over, led by an anchoring 102 from 134 balls from opener Chris Stewart.
With Stewart shoring up an end, Mark Fraser (71) joined him to lead their team through to 190-3 by the end of the 37th over, and although Marist could not launch from there the way they would have liked, a typical six from Sam O'Leary (13) was the standout amongst the tail-enders low scores to click over 250.
Wereroa's Matthew Good (4-40), who was in contention with United's Tom Lance for the season MVP honours, led the home team fightback along with Jaedyn Dawson (3-49) and Carl Trask (2-32).
But Good missed his chance to make up ground on Lance when he was caught by O'Leary off Nick Harding (2-26) in Wereroa's first over, and although Adam Simonsen (55) was scoring well with support from Thomas Morgan (13), they were also eventually caught out.
Trask (65 not out) held his ground in the middle order, but rapidly ran through batting partners as bowlers Angus Dinwiddie (2-41), Sam Beard (2-17) and O'Leary (2-18) would catch up with the lower order who were trying to survive to the late overs, ultimately dismissed for 186 in the 37th.
In the Horowhenua-Kapiti derby game between the beaten semifinalists, Kapiti Old Boys finished with 76 run win over Levin Old Boys in a rain-shortened 45 over match, scoring 220-8 and then bowling the visitors out for 144.
Meanwhile, it was a disappointing end to the women's national Twenty20 competition for the Central District Hinds and their Whanganui allrounder Jessica Watkin with a eight wicket loss to the Auckland Hearts on Saturday.
At the Lincoln University grounds, the Hinds raised 114-8 from their 20 overs, with Watkin opening with 24 from 21 balls, including three boundaries and a six.
But otherwise, only Hannah Rowe with 35 reached double figures as the target set looked inadequate. It soon proved that way as Auckland smashed 117-2 by the 17th over, led by Sara McGlashan (51no) and Maddy Green (56no), as they got the winning runs in Watkin's fourth over.
All games yesterday, including the Hinds match with the Otago Sparks, were abandoned due to rain.
This meant the Hearts (6-3) could not catch the Wellington Blaze (7-2) on top of the points table, while the Hinds (3-6) had to settle for fourth overall.
Scoreboards
Marton 253 (C Clare 131, J Wilson 34, T Bidois 25; H O'Leary 4-28, F Kinnerley 2-11, S Suri 2-24) bt Tech 169-6 (J Dorgan 36, H O'Leary 29; B Galpin 2-25, T Bidois 2-33) by 10 runs (Duckworth/Lewis method).
Marist 258 (C Stewart 102, M Fraser 71; M Good 4-40, J Dawson 3-39, C Trask 2-32) bt Wereroa 186 (C Trask 65no, A Simonsen 55; S Beard 2-17, S O'Leary 2-18, N Harding 2-26, A Dinwiddie 2-41) by 72 runs.
Kapiti 220-8 (J Miles 61, T Halbert 55no, P McNabb 29, Z Benton 23, M Harrison 21; F Bartholomew 3-40, D Sanson 2-30, K MacLachlan 2-35) bt Levin 144 (R Taylor 29, D O'Brien 22; Z Benton 5-44, C Beleski 3-18) by 76 runs.