Australia had eight days' rest before defeating Samoa 44-12 in the Rugby League World Cup semi-final, booking a final against New Zealand.
New Zealand had one more day to recover than Tonga and won their semi-final 34-10 on Saturday.
The defeats have prompted fans to question whether the tournament schedule favoured the two finalists, after Tonga and Samoa appeared to tire.
Tonga returned to action after a bruising group-stage clash with Samoa the previous Sunday. Its group schedule also included England, while Australia and New Zealand each faced only one top contender in their groups.
New Zealand had finished its group campaign with a 78-0 win over Fiji. Kalyn Ponga's return helped the Kiwis beat Tonga, with Ponga named player of the match.
Tonga faded in the second half, and Robert Toia's absence was another setback. Samoa started strongly against Australia, but tough calls shifted momentum; the team struggled defensively and grew frustrated as the match wore on.
Some fans argue Tonga and Samoa's demanding group-stage encounter left them short of energy for the semi-finals. Others suggest Australia and New Zealand may have been disadvantaged by lacking a competitive match before the knockout round.
Fans are calling for a more even group-stage format at the next World Cup.