Papua New Guinea all but sealed a semi final berth at the Oceania Under 17 Women's Football Championship while Group B rivals Vanuatu kept alive their hopes of a top four finish.
The Cook Islands took an early lead against PNG when captain Susan Williams headed home after ten minutes for the host nation's first goal of the tournament.
PNG defender Belinda Giada equalised six minutes before halftime and scored what proved to be the match-winner five minutes later in wet and windy conditions.
In the early game, Vanuatu bounced back from a heavy first-up defeat to edge Fiji 3-2.
Annie Gere opened the scoring just before halftime, with Cynthia Ngwele making it 2-0 three minutes into the second period.
Fiji surged back into contention as Cema Nasau and Koleta Likuculacula struck in the space of three minutes to set up a tense finish.
But it was Leimata Simon who got in behind the defensive line to slot the winning strike in 83rd minute.
After a heavy defeat in their opening match, coach Joel Rarua was relieved to get off the mark.
"Unfortunately we had more chances to score but the players couldn't be able to [convert] the goals early in the first half. We managed to conceded two goals halfway in the second half to equalise with us but we kept trying to push the central midfield to find all the alternatives to get over the strong defence of Fiji and we managed to get over that in order to score and we managed to win the game".
PNG lead Group B with a maximum six points, three clear of Fiji and Vanuatu, with the Cook Islands yet to get off the mark.
New Zealand top Group A from New Caledonia, Tonga and Samoa.
Today is a rest day, with the final round-robin matches in the respective groups to be played concurrently tomorrow.