Holders Thailand escaped with a 0-0 draw against Malaysia in the first leg of their AFF Cup semifinal at Kuala Lumpur's Bukit Jalil Stadium on Saturday.
The hosts, roared on by a sell-out crowd of more than 85,000, kept the five-time winners of the regional tournament on the back foot for much of the 90 minutes but failed to establish a lead ahead of the second leg in Bangkok on Wednesday.
Malaysia started brightly against Milovan Rajevac's side who struggled to contain Gambia-born midfielder Mohamadou Samareh.
Safawi Rasid skied an early effort over the bar before Samareh sent a 26th minute shot narrowly wide of Thai goalkeeper Chatchai Budrom's right post as Malaysia threatened.
Samareh put the Thais under pressure again two minutes later but was forced to shoot off target.
Thailand had comfortably secured their spot in the last four but lacked the assuredness that had seen them finish top of their group ahead of the Philippines.
Adisak Kraisorn, the tournament's leading scorer, had a quiet evening, with the forward thumping an attempt from outside the area well over the bar just before the hour mark in a rare sight of goal for the Thais.
The winners of the tie will meet the Philippines or Vietnam in the final, with the Filipinos due to host the first leg of their semi-final in the southern city of Bacolod on Sunday.