Playing in their first home Test since June 2000, the far more experienced Bati side were completely outplayed by the Kumuls at the National Stadium in Suva.
The win again showcased Papua New Guinea's depth, showcasing the country's push for NRL admission in the next round of expansion.
It also marked a perfect start to Jason Demetriou's coaching tenure, with a national team featuring a mixture of Queensland Cup players, Super League journeymen and Jack de Belin as the sole NRL representative from this year.
Jason Demetriou has made a successful start to his stint as PNG coach. (Dan Himbrechts/AAP PHOTOS)
But that inexperience mattered little, with NRL-player-turned-Salford-fullback Nene Macdonald the best on field and Kyle Laybutt also outshining the Bati's halves.
One-time North Queensland winger Robert Derby also had a big night, twice intercepting Viliame Kikau passes to create tries for the Kumuls.
It was in that fashion that Papua New Guinea opened the scoring against the run of play, when Derby picked off a Kikau pass and went 90 metres untouched.
MacDonald then imposed himself on the game, finishing with 277 metres, 10 tackle busts, two linebreaks five offloads.
The No.1 set up the crucial try of the night to make it 10-0 in the first half when he pushed his way through five defenders and put hooker Judah Rimbu over.
He also had a try of his own after the break, when he loomed up in support play to score after Derby's second intercept.
In contrast, Fiji had 10 players who featured in the NRL this year but couldn't take their chances.
While Kikau's intercepted pass ruined one of their early attacking raids, they three times kicked the ball dead on the last in the first half alone.
A lack of recognised halves showed, with the only points coming in the second half when Kevin Naiqama sent winger Semi Valemei over and Maika Sivo scored on full-time via a loose ball from a kick.
The Kumuls' win means they will advance to the Pacific Cup playoff as the top-ranked team in the Bowl division, if they beat Cook Islands in Port Moresby on November 3.Â
The result also has the potential to have implications in next year's NRL season for Wests Tigers captain Apisai Koroisau.
Banned for the Pacific Championships due to a dangerous throw, his suspension will continue into the opening round if the Bati do not recover to top the group and reach the playoff.
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