Shunsuke Nakamura, Yasuhito Endo and Kengo Nakamura scored for the winners, while Salman Isa pulled one back for the hosts and Marcus Tanaka scored an own goal toward the end to give Bahrain a glimmer of hope. Australia, Qatar and Uzbekistan are the other teams in Group 1, with the winners and runners-up going through to the finals to be held in South Africa.
The third placed side will clash with its corresponding team in Group B and the winner of that match will take on New Zealand (the winner of the Oceania zone) in the final play-off for a possible fifth spot for Asia at the finals. The Qataris started their campaign with a 3-0 win over Uzbekistan in Doha.
Japanese coach Takeshi Okada attributed his team's victory to a fine team effort. "We were in control right through. We want to carry this good work forward," he said.
Bahrain coach Milan Macala blamed the poor first-half for his team's defeat. "We did not play according to our plans. The team looked different than what I expected. It lacked spirit," said the 64-year-old Czech. The Japanese controlled the game very well and that was a psychological problem for us. I'm satisfied with our second half effort, but not happy with the result."
This match, played in stifling desert heat and humidity, came alive after 15 minutes of hit-and-chase forays between these two familiar but fiercely bitter foes who had also met in the last round. Japan kept asserting their superiority with Saint Etienne striker Daisuke Matsui and Makoto Hasebe keeping the Bahrain defenders Sayed Mohammed Adnan and Mohammed Hussain busy.
Japan's perseverance paid off in the 18th minute when Celtic star Shunsuke Nakamura scored a terrific free-kick. Nakamura stayed cool as the free-kick, from 10 metres outside the penalty area, was delayed with the Bahrainis taking their time in setting up a defensive wall. Endo ran a dummy which unsettled the Bahrainis and Nakamura struck a powerful left-footed shot past Bahrain goalkeeper Jaffar.
Bahrain made a brave attempt to bounce back two minutes later when the hard working Salman Isa made a solo effort down the middle. But Japanese goalkeeper Seigo Narazaki fended off Isa's powerful long-range effort. That was Bahrain's best attempt in the first-half as the hosts struggled to match the fast-moving and quick-passing Japanese.
Moreover, Ala'a Hubail's inability to break free upset the rhythm of the midfielders and left Isa desperately short of supply at the top of the attack. Japan doubled the lead in the 44th minute with Nakamura starring again when his shot at goal struck Fouzi Aaish's right hand. Singapore referee Bashir Abdul Malik had no hesitation in pointing to the spot and Endo converted the penalty.
Japan could not be denied a third goal and Kengo Nakamura obliged with a fine strike with five minutes left to play. However, it was still not all over as Isa pulled one back with three minutes to go and then Japan goalkeeper Narazaki misjudged a headed back-pass by Tanaka.