Tonga called its 34-10 semifinal defeat by New Zealand a "missed opportunity", after fifth-tackle plays hurt the side in Newcastle's extreme weather.
Australia's 44-12 victory over Samoa secured another World Cup final against New Zealand, at Suncorp Stadium next Sunday night.
The tournament has shown Tonga and Samoa closing in on England, now the third- and fourth-best teams in the world.
Their group-stage meeting last week was the tournament's standout match, and further Pacific contests are expected to shape international rugby league.
Both sides have room to improve before the next World Cup in four years, with much of their current core likely to remain.
But Australia and New Zealand remain the teams to beat: the Kangaroos are pursuing a fourth consecutive title, while New Zealand reaches its first final since 2013.
Samoa beat England in the World Cup semifinals four years ago and challenged New Zealand in last year's Pacific Cup, but has yet to defeat Australia.
The team's passion and emotion need to be controlled on the biggest stage.
Samoa took a 2-0 lead from a penalty, then conceded control as Tom Dearden and Jacob Preston scored against defenders Jazz Tevaga and Francis Manuleleua.
Australia led 26-2 at halftime after a dominant opening 50 minutes.
Spencer Leniu made an early error, was sin-binned for dissent before halftime, then made another mistake after returning.
Samoa briefly threatened when Stephen Crichton scored after a Reece Walsh error, making it 26-8 with 35 minutes left.
But Ata Mariota forced an offload, Beniah Ioelu lost the ball, and Walsh scored soon after to end Samoa's comeback hopes.