Vancouver - South African-born fullback Kotaro Matsushima scored the clinching try for a 14-man Japan to give the visitors a 26-22 win over Canada on Saturday.
Hooker Aaron Carpenter scored the fourth Canadian try with a minute remaining, but strong defence by Japan helped secure the win.
Back rower Yoshida Hosada was sent off in the 54th minute, forcing the Japanese to play a man down for most of the second half.
Hooker Takeshi Kizu scored a first-half try for Japan, which led 13-12 at the break. Japanese flyhalf Yu Tamura kicked four penalties and two conversions for 16 points.
Taylor Paris, Ray Barkwill and Jamie Cudmore scored the other Canadian tries.