Tonga inflicted a second loss on Pacific Nations Cup defending champions Japan thanks to a 24-20 victory on Sunday.
Tonga outscored Japan three tries to two to post its first win of the tournament following an outstanding individual performance from Japan full-back Ayumi Goromaru, who scored a try in totaling 15 points.
After trailing 17-10 at half-time, Japan began the second half strongly, splitting the Tonga defense with a bullocking run by first-half try-scorer Hendrik Tui.
Japan was awarded a penalty and Goromaru lined up a relatively easy kick from 25 meters. His attempt hit the post, and before the Tongan defenders could react, the 26-year-old full-back dashed in, grabbed the rebound and scored.
He added a conversion from close to the spot from which he had attempted the penalty to tie the scores at 17-17.
Paula Kaho scored the winning try for Tonga after both sides had defended doggedly. Fly-half Kurt Morath added the conversion to lift Tonga to a 24-17 lead after previously converting tries by Alaska Taufa and Taniela Moa.
Goromaru kicked a late goal to finish with a try, two conversions and two penalties.
Japan: 15 Ayumu Goromaru, 14 Toshiaki Hirose, 13 Ryan Nicholas, 12 Harumichi Tatekawa, 11 Hirotoki Onozawa, 10 Kosei Ono, 9 Atsushi Hiwasa, 8 Hendrik Tui, 7 Takamichi Sasaki, 6 Yuta Mochizuki, 5 Hitoshi Ono, 4 Shinya Makabe, 3 Hiroshi Yamashita, 2 Takeshi Kizu, 1 Yusuke Nagae.
Rpelacements: 16 Ryuhei Arita, 17 Kensuke Hatakeyama, 18 Shoji Ito, 19 Takashi Kikutani, 20 Jun Fujii, 21 Tomohiro Senba, 22 Yasunori Nagatomo.
Tonga: 15 Viliame Iongi, 14 Siale Piutau, 13 Alipate Fatafehi, 12 Sefa Vaka, 11 Alaska Taufa, 10 Kurt Morath, 9 Taniela Moa (c), 8 Viliami Maafu, 7 Sione Vaiomounga, 6 Steve Mafi, 5 Joe Tuineau, 4 Josh Afu, 3 Kisi Pulu, 2 Ilaisia Maasi, 1 Tevita Mailau.
Rpelacements: 16 Viliami Pola, 17 Sila Puafisi, 18 Paula Kaho, 19 Pepa Koloamatangi, 20 Thomas Palu, 21 Mafileo Kefu, 22 Edmond Paea.