FC Tokyo full-back Yuto Nagatomo and Kawasaki Frontale midfielder Kengo Nakamura handed Japan a 2-0 half-time lead before Shimizu S-Pulse striker Shinji Okazaki and Albirex Niigata's Kisho Yano sealed the win in the second half.

Japan, who beat Chile 4-0 on Wednesday, can secure their place at next month's World Cup finals with a win against Uzbekistan in Tashkent on Saturday before the remaining group games against Qatar and Australia.

"We played with good rhythm for the first 20 minutes, but after that, our players slowed down the pace and played with 80% of their ability. I had to tell them to remember the purpose of this game, which is to beat Uzbekistan," said Japan coach Takeshi Okada.

"We played very aggressive football in the second half and produced goals in good ways. That made me feel content with the game.

"We scored goals while keeping a clean sheet in the last two matches, however, that won't give us any guarantees in the coming Uzbekistan match. We should reset our focus to come home with a win there by any means."

Japan, who welcomed Celtic midfielder Shunsuke Nakamura, Wolfsburg forward Yoshito Okubo and Urawa Reds defender Marcus Tulio Tanaka back into the squad, enjoyed good early possession with Belgium content to adopt a defensive style.

And after Japan went close on several occasions as Okazaki rattled the Belgium woodwork, the home side opened the scoring after 21 minutes as Nagatomo converted from a tight angle from Kengo Nakamura's pass.

Kengo Nakamura doubled the lead two minutes later as he fired home from the edge of the area as inexperienced Belgium, who were without the majority of their regular squad due to their commitments in Europe, struggled to deal with Japan.

They did come close as Kevin Roelandts fired wide after 30 minutes, but normal service was resumed six minutes before the break as Makoto Hasebe's lob hit the Belgium crossbar.

Okazaki, who scored twice in the 4-0 win over Chile, added a third on the hour mark as he connected with Okubo's crisp cross.

And with 12 minutes remaining substitute striker Yano slotted home Nagatomo's cross from close range.

"There was too much distance between the quality of Japan and our quality today." said new Belgium coach Franky Vercauteren.

"There were maybe some excuses that there were more players used with less rest between of the two games so close together. But those excuses are not enough to say the quality they had was much bigger today. They deserved the result. We did our best, though."