The New Zealand Heartland XV could not follow up Wednesday's victory over the Vanua XV, who rebounded with a 15-7 win at a sodden Lawaqa Park in Sigatoka on Saturday.
Torrential rainfall that only ended about 10 minutes before kickoff left the sidelines waterlogged and the ground very wet underfoot, making execution in key phases extremely difficult.
Having made six changes from the side who beat Vanua 12-7 earlier in the week in Lautoka, coach Mark Rutene looked to his most experienced players for the inside back combinations with North Otago's Robbie Smith and Wairarapa Bush's Tim Priest in the halves, supported by West Coast's Sione Holani coming in to partner Wanganui's Penijamini Nabainivalu in the midfield.
The final lineup was a mixture of the Wednesday squad and those who had played in the 29-19 loss to an experienced NZ Marist at Te Aroha the previous Saturday.
But in the end, what proved the difference was a couple of key errors on the rare moments to attack the tryline, and a growing penalty count in the second stanza which let the home side take several shots at goal, finally getting the last one inside the final ten minutes.
West Coast lock Sam Liebezeit came in to partner Wanganui's Campbell Hart, the only player to wear the same starting jersey in all three tour games, and Heartland had an early chance when they drove to the line from a lineout.
However, they were held up and then lost the ball from the subsequent 5m scrum, with Vanua then showing despite the wet they are still dangerous with ball in hand, getting through the defensive line on a 60m breakaway.
Vanua likewise had an attacking 5m scrum, but were penalised to let Heartland clear, while the home side also made some costly errors – losing the ball at the tryline and then knocking it on after a series of passes from a snatched intercept.
A kick by Smith from another scrum saw Vanua cough up the ball, with Heartland getting a 5m scrum and then setting for another one after receiving a penalty, but again lost ball and an infringement let the home side off the hook.
On an afternoon where any kind of points could be crucial, Vanua pounced after a clearing for touch from their line, and when the ball didn't find the line, a wayward Heartland pass was dropped and fullback Nesiasi Moala swooped to run 60m for a converted try.
The Fijians took their 37th minute deadlock-breaking try into the break, and Heartland just couldn't reply as one attacking penetration into Vanua's 22m took 21 phases of control, until the New Zealanders were penalised.
A turnover at scrum time again let Heartland kick into the attacking 22m, but again they were repulsed by good defence, Vanua getting a scrum at their tryline to boot out of trouble.
The home side had three golden chances to put themselves out of striking distance with penalty kicks in the 52nd minute and then back-to-back in the 62nd and 64th, but missed the lot, with the New Zealanders looking to their bench.
Another penalty and this time Vanua opted to the sideline, and although Heartland stole the ball, the subsequently dropped it and three phases later the Fijians and forced their way over for an uncatchable 12-0 with eight minutes left.
The whistle kept sounding against a desperate Heartland XV, five times in a row, and that let Vanua close enough for another three-point attempt, which was landed for the matchwinner.
With two minutes remaining, there was just enough time for the New Zealanders to finally crack some consolation points, as King Country reserve winger Alex Thrupp scored, converted by Horowhenua Kapiti fullback Himiona Henare.
So ended the season for the best of local game's amateur players, with the Heartland XV having played four matches in a calender year for the first time since their formation in 2006.
There was the rare chance to face a full international test squad when the side lost to a Manu Samoa side heading to the Rugby World Cup, 36-19 at Eden Park on August 31.
That game was held during the second round of the Heartland Championship, with 13 of the players involved then backing up in the 26-man squad for the three end-of-season games with NZ Marist and the Fiji tour.
Thames Valley's Brett Ranga captained the side in all four games, twice from flanker and then No 8.