Junichi Inamoto scored his second goal of the World Cup to secure Japan's 1-0 victory over Russia in their Group H clash on Sunday.
Atsushi Yanagisawa tapped a pass to the unmarked Inamoto at thegoal mouth and the Arsenal midfielder struck over Russian keeper Ruslan Nigmatullian into the net.
Japan, who have collected four points from two games, are in a favorable position to reach the second round. Russia, who beat Tunisia 2-0 in their opening game, place second with three points.
Belgium are in third place with one point with Tunisia last with zero.
Parma midfielder Hidetoshi Nakata nearly put the co-hosts 2-0 ahead in the 71st minute when his 25-meter shot flew over Nigmatullian, only to be blocked by the cross bar.
Russia's best chance came in the 59th minute as Vladimir Beschastnykh rounded Japanese keeper Seigo Narazaki to put his shot into the side netting.
The Japanese began aggressively with Inamoto firing just wide from 25 meters in the fifth minute and Hidetoshi Nakata blasting just over the bar in the 28th.
Russia wasted a wonderful chance to open the scoring in the 40th minute as Andrei Solomatin charged deep into Japanese area and left it back for Igor Semshov, who went down before reaching the ball.