Having incurred the wrath of head coach Ivica Osim after being held by Qatar in their opening game, the three-time Asian Cup winners made light work of their latest Middle Eastern opponents at the My Dinh National Stadium.

Two goals from Naohiro Takahara coupled with a Shunsuke Nakamura penalty saw Japan take top spot in Group B on goals scored from co-hosts Vietnam.

With the UAE now certain to catch an earlier-than-expected flight home, a draw against Vietnam in their final group game next Monday would ensure Japan of a berth in the knockout phase.

Bruno Metsu's UAE side, who were beaten 2-0 by Vietnam in their first match at Asia's premier tournament, started relatively brightly, but it was Japan who created the game's first decent chance.

In the fifth minute, defender Yuichi Komano cleverly cut inside his marker before unleashing a well-struck shot that UAE goalkeeper Majed Nasser did well to gather.

In what would prove to be a rare moment of UAE brightness, star striker Ismail Matar's long-range effort then brought the very best out of experienced Japan custodian Yoshikatsu Kawaguchi.

With Japan pressing, the breakthrough came after 22 minutes.

A short corner routine by the east Asian giants led to the UAE defence giving far too much room to dangerman Nakamura.

The Celtic midfielder delivered a delightful cross that Takahara headed home with ease, to register his second goal of the tournament following the Eintracht Frankfurt man's earlier strike against the Qataris.

Just five minutes later in what was a woefully lopsided first period, Japan doubled their advantage.

Following a delightful build-up, Akira Kaji found Takahara in space on the edge of the UAE box. In a flash, the 28-year-old unleashed a terrific shot that screamed past Nasser.

Seiichiro Maki went close to grabbing Japan's third, the JEF United Chiba favourite heading over from close range before, with just three minutes remaining in the half, referee Thongkan awarded Japan a penalty following Nasser's rash challenge on Yasuhito Endo. Nakamura dispatched the spot-kick with customary aplomb.

Within seconds of the restart, a lively Endo, fed by a wonderfully floated Takahara pass, smashed a shot into the side-netting as the UAE came perilously close to conceding yet again.

With Japan dominant, the UAE's self-control went walkabout - indiscipline that resulted in Basheer Saeed being given a straight red card in the 54th minute for a terrible lunge on Keita Suzuki.

Nakamura narrowly failed to rub salt into UAE wounds when Nasser smartly turned away his effort from the resulting free-kick.

Substitute Saeed Al Kaas gave the UAE, much improved in the second period, a brief glimmer of hope after 66 minutes when, thanks to a superb run and slide rule pass from Ahmed Mubarak, he fired home past Kawaguchi.

Matar then came close to reducing the deficit even further shortly after, but it proved to a false dawn for the UAE as their opponents soon regained the upper hand, with Endo and Koki Mizuno both threatening to stretch Japan's lead.

With no further goals to entertain a sparse Hanoi crowd, Japan were left to dream of a fourth continental title and Metsu surely pondering where it all went wrong for his UAE outfit.