Defending champions Thailand will take on Vietnam in the final of the Asean Championship after Mano Polking's hosts notched up a 3-0 win over Malaysia on Tuesday to overturn a first leg deficit and secure their place in the tournament decider.The Malaysians had held a 1-0 lead from the first leg in Kuala Lumpur but goals from Teerasil Dangda, Bordin Phala and Adisak Kraisorn earned the six-time champions the result needed to advance to the country's 10th final in 14 tournaments.Vietnam, who defeated Indonesia on Monday to progress to the final, will host the first leg of the showpiece in Hanoi on Friday with the return in Thailand four days later.It took the Thais 19 minutes to pull level on aggregate when Teerasil, the tournament's all-time leading scorer, rose unmarked to firmly head Theerathon Bunmathan's cross from the left past Malaysian goalkeeper Syihan Hazmi.Ten minutes into the second half Thailand doubled their lead on the night to go ahead on aggregate when Bordin swept in Ekanit Panya's cut back from the right.Substitute Adisak, who had replaced Teerasil at halftime, then put the result beyond doubt in the 71st minute, converting from close range after initially hitting the post following Suphanan Bureerat's centre.Vietnam and Thailand will be meeting in the final of the regional competition for the first time since 2008, when the Vietnamese won 3-2 on aggregate to claim the trophy.