In the final minutes at CommBank Stadium on Sunday night, Sua Fa’alogo chased the left corner with Samoa two points down and 29,411 people on their feet. His foot touched the sideline, the try was ruled out, and Tonga had won 20–18.

Four years earlier, at Warrington, the same teams played out the same scoreline in the other direction, with Samoa winning a World Cup quarter-final 20–18. This time the margin came down to the kicking tee.

Both sides arrived unbeaten. Samoa had beaten France 78–4 and Papua New Guinea 64–6, and Tonga had beaten England 30–12 and Lebanon 36–0. Between them they had scored 208 points and conceded 22, so a two-point game was a different kind of night for each.

Samoa scored four tries to Tonga’s three. Brian To’o crossed twice, and Hamiso Tabuai-Fidow and Ronald Volkman once each. But Samoa converted only one of their four, Volkman’s own, while one attempt from Chanel Harris-Tavita hit the upright. Isaiya Katoa converted all three Tonga tries and added a penalty. Three missed conversions cost Samoa six points, and the game finished two apart.

Tonga started the better of the two. Dallin Watene-Zelezniak had a try ruled out in the 13th minute when his foot grazed the sideline, but Rob Toia scored a solo try about 13 minutes later, Katoa kicked a penalty, and Tonga led 8–4 at the break after To’o’s first try. Jojo Fifita extended it to 14–4 early in the second half after a long pass from Tui Lolohea.

Samoa’s comeback came through To’o, who scored again from a Harris-Tavita pass before the five-eighth left the field with a hamstring injury. Tabuai-Fidow and Volkman followed, and Samoa led 18–14 with under 12 minutes to play. The missed kicks mattered because the lead was only four.

Addin Fonua-Blake settled it in the 72nd minute with a run through the middle of the Samoan defence, and Katoa’s conversion put Tonga ahead. That left Fa’alogo’s chase as the last chance, with the sideline ruling mirroring the call that had denied Tonga early.

The result sends Tonga into a semi-final against New Zealand in Newcastle on Saturday 7 November. Samoa meet Australia at Allianz Stadium the following day. Both sides are still in the tournament, which is the right context for a result this small. Tonga finish the group with three wins from three. Samoa finish with two big wins and one narrow loss, and the edge Tonga found came from the part of the game that does not show up in the highlights.