Tamada's second of the thrilling semi-final, three minutes into extra time, came after defender Japan Yuji Nakazawa had equalised with a diving header with just seconds remaining of normal play.

The Kashiwa Reysol forward wriggled past Mohamed Juma and Bahrain captain Faisal Abdulaziz before shrugging off defender Hussain Baba to plant a right-footed shot past keeper Ali Saeed, sparking wild celebrations on the Japan bench.

Japan now have the chance to defend their title in Saturday's final, their third in 12 years, against the winners of China and Iran who play later Tuesday.

Tamada's effort completed a roller-coaster encounter which saw the lead change hands four times.

Bahrain, population 680,000, had looked to have one foot in the final when substitute Duaij Nasser pounced for his second of the tournament with just five minutes remaining.

However, Nakazawa's header earned 10-man Japan a reprieve allowing Tamada to complete the turnaround.

Tournament top-scorer A'ala Hubail, who had already netted twice, went agonisingly close to taking the game to penalties but inexplicably mistimed his tap-in to an empty goal.

Hubail had earlier ignited an incident-packed match after burying a right-footed shot past Japan's keeper Yoshikatsu Kawaguchi on six minutes.

The goal stung Japan into action, with most of their moves coming through Alex Santos down the left wing. Striker Takayuki Suzuki missed an open goal from an Alex cross and Shunsuke Nakamura should have done better with another dangerous ball from the Brazilian-born wing-back.

Japan's cause was dealt a serious blow when Endo was given his marching orders after brushing past Mohamad Salmeen, who went down clutching his face.

But the defending champions, severely weakened by injuries and Olympics call-ups, hit back after the break when Nakata rose at the near post to head in a corner.

Tamada was given space to rifle a right-footed shot past Ali Saeed just minutes later.

Bahrain pressed their man advantage with Mohamad Al Wadaei setting up A'ala Hubail for his fifth of the tournament with just 20 minutes to go.

Substitute Nasser, the Bahraini league's top-scorer, notched his second of the campaign to spark joy on the Gulf team's bench with five minutes to go.

However, the celebrations proved premature as defender Nakazawa put his diving header past Saeed with just seconds remaining of normal time.

Bahrain, playing in just their second Asian Cup, were also reduced to ten men when Al Wadaei was red-carded for a foul on Nakamura in extra-time.