Wingers Vuate Karawalevu and Ponepati Loganimasi both scored two tries as Fiji secured a seventh Pacific Nations Cup title with a convincing 41-17 victory over Japan in the final in Osaka on Saturday.
Karawalevu scored his first try off a kindly bounce from a kick out of defence in a tight first half and crossed again 10 minutes from time as the Brave Blossoms wilted in the heat of the Hanazono Rugby Stadium.
Paris Olympics Sevens silver medallist Loganimasi came on for his test debut in the second half and quickly made his mark in the 15-man game with tries in the 59th and 75th minutes.
Japan, looking to hand Eddie Jones the first trophy of his second stint as coach, held their own for the best part of an hour of the contest despite playing with 14 men for 10 minutes around the break when hooker Mamoru Harada was sin-binned.
The home side also scored the pick of the tries through Dylan Riley in the 20th minute, the centre cutting through the first line of defence with a dummy and a sidestep before a chip and chase took him past the cover defenders.
Three tries in the last 20 minutes and 16 points from the boot of Player of the Tournament Caleb Muntz, though, ensured the Fijians would retain the trophy in the first year of the tournament's new format.
"The bond in this group is great and we are looking to build on this on the November tour and towards the next World Cup," said Fiji captain Tevita Ikanivere.
Jones, who led Japan to the title in 2014 during his first spell as coach, said the inexperience of his team had probably cost them.
"We've got no excuse, Fiji are very deserved champions," the Australian said.
"But a couple of our young guys today struggled with the occasion. Unfortunately, the only way you learn about that is to (experience it) and I'm sure they're going to be better for it."
Earlier at the same ground, replacement back Melani Nanai scored a try two minutes from time to give Samoa an 18-13 win over the United States in the third-fourth playoff match.
- Reuters