Ross Kinnerley (4-29) and Nick Harding (2-24) had another dominant opening spell.
However, this time Smith shored up his end, scoring 77 from 81 balls, supported by captain Mark Fraser who was on the verge of a very special afternoon.
Smith finally gave away a catch off the bowling of Jessica Watkin, but the massive partnershp took them to 167-5 from 32 overs, as Marist had solidified their recovery.
Fraser carried it on, batting with the tail and lifting his run rate to score 143 not out from 168 balls, a higher individual total than many teams have made this campaign.
He was supported by Jonathan Steward (20) and the rest of the tail staying with him, and at the end took the long wood to Tech allrounder Akash Gill, launching the ball over the boundary rope four times, to go with his 17 boundaries.
Marist's 284-8 eclipsed Tech's 243, made a fortnight ago, as the largest total of the competition, and because of extra time taken, under the rules Tech started with less than the normal 48 overs remaining to try and make the total.
It did not matter anyway, as they were dismissed in the 28th over for 114.
Another returning Marist player in paceman Sam Beard got amongst the Tech openers with a great haul of 5-18, as key top order players in Matthew Bennett, Gill and Calum Coker all fell cheaply.
Enjoying being back at home, Smith continued his impact with 3-38, getting the main hopes in the middle order, as captain Dominic Lock (37) found some form but could not anchor the run chase, while the next best contributions were Kane Watkin (17), Ross Kinnerley (17), and Nick Harding (15) - the latter two starting confidently but falling to catches.
Over at the school grounds, Collegiate completed a good return to playing Premier 1 with a team run chase to beat Saracens, who had also included a couple of Palmerston North school players to bolster their depleted ranks.
Collegiate got off to the perfect start with newly minted representative bowler Angus Dinwiddie getting Scott Oliver with the first ball, on the way to taking 5-30 from his spell.
Charlie Greatbatch was hard to get away with his 2-27 from eight overs, as only returning veteran Dominic Rayner (30) able to stick around in the top order.
The middle order of Josh Trillo (29), Tom Westwood (31), and Chris Rayner (45 not out) looked to bat through the full 52 overs, but Rayner ran out of partners after Dinwiddie exposed the tail.
In reply, Collegiate started posititively with James Pennefather (44) and Harry Cave (28) willing to hit over the top if need be, while still waiting for the bad balls as scoring at a swift rate is never easy on the school pitch.
Although no-one cracked on for a big score, every batsman contributed as Sam Sheriff (17), Dinwiddie (25), Nick O'Leary (22) and Greatbatch (18) helped the side slowly make their way to the promised land in the 49th over.
Collegiate will now focus on their interschool games in the latter half of the summer, while the four club teams will prepare for the upcoming national club one-day competition qualifiers.
Results
Marist 284-8 (M Fraser 143no, B Smith 77, J Steward 20, R Kinnerley 4-29, N Harding 2-24) bt Tech 114 (D Lock 37, S Beard 5-18, B Smith 3-38) by 170 runs.
Marton Saracens 175 (C Rayner 45no, D Rayner 30, T Westwood 31, J Trillo 29, A Dinwiddie 5-30, C Greatbatch 2-27) lost to Collegiate 178-6 (J Pennefather 44, H Cave 28, A Dinwiddie 24, N O'Leary 22, J Trillo 2-52) by four wickets.