In reply, Marist pinned United down, as Whiteman (61 not out) and Andrew Cording (32) tried to pull their side through.
"We tried to get close but we were pushing seven an hour," said Cording.
"They tied us down and then we couldn't get on top of them."
Captain Gerard Hobbs also contributed with 39, for his team which was missing a few campaigners with representative duties, injury and other weekend commitments.
The chase was not without some controversy in the form of United's leading hope Tom Lance being run out in "unsportsmanlike" circumstances.
Cording said after playing a delivery Lance left his crease to flick the ball up to a fielder, at which point the Marist keeper whipped off the bails.
While a legal dismissal, a player can be recalled for this but Marist needed the scalp, Cording said.
"It's no excuse but we thought it was a bit poor."
The loss may not hamper United too much as Collegiate is going to default their last match of the competition, leaving United a chance to wrap Premier 1 up with a win next week against Saracens.
Collegiate had a big 110 run win against Wanganui High School.
Results
Porter Hire Premier 1
Silks Audit Marist 232 (F Kinnerly 73, B Turner 44, J Whiteman 3-51, C Ashworth 2-28) bt David Jones Motors United 204-7 (G Hobbs 39, J Whiteman 61no, A Cording 32, S O'Leary 2-28, L Burgess 2-21).
WCS 272-7 (A Halbert 107, M Innes 59, T Albert 55, K Watkins 2-45) bt WHS 162-8 (K Watkins 35, M Innes 4-37).
Porter Hire Premier 2
WHS 84 (A.Cobb 5-18) lost to WHSOB 86-4 (A.Cobb 47).
Marton Saracens bt WCS by default.
Tech OB 150-5 (F Berry 40, J Judd 32no, M Pennefather 2-13) lost to United 154-4 (R Verma 54no, M Pennefather 34no, B White 3-35).