Japan lifted the Pacific Nations Cup after a 20-15 win over Fiji in Tokyo on Saturday, gaining revenge after losing to the same opponent in the previous two finals.
Eddie Jones's Japan settled a tight game when substitute Samisoni Tua crashed over in the 72nd minute.
It gave Japan their first title since 2019 in a competition that has undergone several changes of format.
Canada earlier claimed third place, edging the United States 19-16.
Japan, who thrashed the USA in the semi-finals, took the lead in the final through an early penalty.
Fiji scored the first try when Virimi Vakatawa barrelled through several tackles to touch down in the 11th minute.
Japan's Sam Greene missed a penalty but a yellow card for Fiji's Mesake Doge soon after gave the home side the numerical advantage.
Japan capitalised when Mamoru Harada scored in the 22nd minute, but Fiji hit back five minutes later with a try from captain Tevita Ikanivere.
Fiji held on to their slender lead in a scoreless start to the second half.
Japan's pressure eventually paid off when Ben Gunter stormed over the line in the 58th minute.
Fiji evened the score with a penalty but Tua had the last word when he barged over for Japan's third try.
Fiji were looking for their third straight title after beating Japan in Osaka in 2024 and in Salt Lake City last year.
The Fijians had a chastening time in the inaugural Nations Championship this year, conceding more than 140 points in defeats to Wales, England and Scotland.