Inness would hold fast against the bulk of the attack in his 72, facing 188 balls in a long afternoon at the crease, while Harding, whose strike rate initially hovered around an unfamiliar 50 per cent, was very watchful - unless a juicy full toss came his way.
Eventually, Harding stepped it up as senior partner as Inness survived a couple of close lbw shouts, both batsmen restoring the innings at 151/5 after 51 overs.
Taranaki requested a ball change as Harding began to play his shots, rapidly catching up to Inness as his own 72 came off 85 balls with nine boundaries.
But afternoon turned to twilight as the day's play wound down towards its agreed 7.30pm finish to account for lost time and Taranaki played smart by bringing on their spinners - trying to get as many overs at the well-set pair as they could.
It worked as with 17 minutes remaining, Harding skied a mis-hit off medium pacer Tom McDougall to be caught, then after carrying his bat all day, Inness' captain's knock ended in the final over when Mattie Thomas clipped the top of the stumps. Now at 186/7 at the close of play, the double whammy hurt Wanganui who were looking to cultivate a decent total above 250 when they returned yesterday morning, and although they did get past 200 the last three wickets fell in quick order to Ryan Watson - a former NZ Under-19 representative and teammate of ex-Wanganui players Henry Collier and Nick Blundell.
Wanganui took 74 overs to reach a reasonable score and Taranaki surpassed it in their 59th, although they were put under early pressure by a fresh Ryan Slight and allrounders Harding and Ross Kinnerley.
Slight made a big breakthrough straight after the lunch break when Sam Fastier missed a pull shot and lost his castle to have Taranaki at 98/4.
However, two very costly drop catches in the slips off Slight's bowling prevented him from getting a crack at the lower order, as Kaylum Boshier (20) carried on with the reprieved Muggeridge.
While Englishman Greg Smith's spinners would get Boshier to miss and be bowled and Sam Beard collected his second scalp to keep Taranaki still teetering at 159-6, Muggeridge put on an orderly 49 run partnership with Jason Dombroski (23no) to see them past Wanganui's total.
Windy conditions were buffering the Tasman Tanning No1 pitch yesterday afternoon as Wanganui prepared for around four hours to save the draw.
They had a horror start to be 23/3 in 12 overs after Watson again turned on the pace.
McIlraith again went cheaply, Morgan Inness could not repeat his Day 1 heroics after being caught for a duck, then main hope Ben Smith again lost his stumps.