McMillan's second-half touchdown looked to have put the visitors on course for a much needed victory, but as happened in the corresponding fixture at Marress, Irvine finished the game short-handed following the sin-binnings of Robbie McVey and Ruchin Filander, and this time they did not have an unassailable lead.
The consolation for Irvine is that with this having been the only game in West 1 to beat the weather, the defeat does no immediate damage to their league position bar giving the clubs around them a game in hand. They entertain one such club, Kilmarnock, next in what is now a must-win game with the Bellsland side only six points ahead.
Irvine edged in front on 13 minutes through the first of three penalties by Ross Bryan before the game was blown open by the sin-binning of prop David Kirkwood shortly afterwards.
Accies wasted no time in capitalising upon their numerical advantage - in a foreshadowing of what was to come - helping themselves to unconverted tries through first Kirkwood's opposite number Fabio Marchetti and then captain Andrew Jackson, to take a 10-3 lead midway through the first half.
The visitors came back into it after Kirkwood's return, and Bryan reduced the deficit with his second penalty five minutes before the interval. There was no further scoring and the sides turned around with the hosts leading 10-6.
Irvine started the livelier of the two teams after the break, aided by an early sin-binning for the hosts, and finally regained the lead through McMillan's try on 55 minutes.
Ruchin Filander, playing at centre - a position he more usually occupies during the rugby league season for Ayrshire Storm - did the initial damage with a good break into the Accies half, and the ball was then recycled and worked to McMillan who crossed in the corner. Bryan was unable to add the conversion but the visitors led by a point coming up to the hour mark.
Bryan notched his third penalty of the afternoon on 65 minutes to take the score to 14-10 in the visitors' favour, but they were to be undone as they managed to have two players sin-binned in quick succession in the dying stages.
Scrum-half Robbie McVey received his marching orders for the second successive game for persistent infringements, before Filander followed him for dissent. To add insult to injury, just prior to Filander's dismissal the visitors had won a penalty on the Accies line which was reversed.
With fifteen men against thirteen a winning try for the hosts was virtually inevitable, and it finally arrived at the death through centre Craig Wright. The conversion was missed and there was still time for the visitors to hit back, but the home side saw this out to leave Irvine once again reflecting on what might have been.
There was better news for Marress, who kept up the pressure at the top of the league with a 24-12 bonus point victory at home to Dalziel 3rds. The tries came from Martin McGonigal, Colin Hunter, Steven Paton and John Murdoch, and Stuart Tracey added two conversions. They are next due to travel to Stewartry.
IRVINE -- K Hobson; S Nunan, C Lang, R Filander, N McMillan; R Bryan,
R McVey; D Kirkwood, M Kirk, S Docherty, T Wright, A Thomson, A Lang,
C Maxwell, I Speirs. Replacements: J Doolan, R O'Neill, C Hobson,
REFEREE -- Graham Filmer