Thailand qualified for the final of the Asean U19 Boys' Championship with a 1-0 victory over feared Australians in Surabaya, Indonesia, on Saturday.
Thailand coach Emerson Pereira took no chances and started with the best men available, with playmaker Thanakrit Chotmuangpak, aided by Caelan Ryan, leading their campaign.
The Thais started well and had an early chance, which Ryan shot over the bar.
Thailand had a lucky break in the 13th minute when Australia's goalkeeper Dylan Peraic-Cullen couldn't collect a back pass from defender Dylan Leonard, giving the Thais a 1-0 edge.
After conceding the own goal, the Australians upped the pressure but the Thai defenders were up to the task and held their ground well.
Australia won a penalty kick during the last five minutes of the first half when Jirapol Saelio committed a foul inside the box, but the match referee reversed his decision after consulting the VAR.
The Thais were reduced to 10 men in the 67th minute when Rapeephat Padthaisong was sent off for a second yellow offence.
The Aussies wrested control of the match but apart from a couple of misses they couldn't manage much.
Pereira praised his men after the victory, saying: "I am proud of my boys for putting up the fight throughout the match. It was a tough and tiring game. We only had a day's rest, but making it to the final of the tournament makes up for it."
The Thai will face the winners of last night's second semi-final between Indonesia and Malaysia in the title showdown on Monday.