The Asian champions Japan won their last warm-up game for the Rugby World Cup next month when they defeated the United States 20-14 in Tokyo.
Fullback Taihei Ueda scored in the right corner in the sixth minute but the Americans replied promptly with a try to winger Kevin Swiryn and led 14-8 ahead at half time after Swiryn crossed again.
Japan scored two second half tries and coach John Kirwan says they defended well, played fast and kept the ball..
Japan is in Pool A with France, New Zealand, Tonga and Canada while the United States will play Australia, Ireland, Italy and Russia in Pool C.
