(Praweenwat Boonyong 24 pen)
It has become an all too familiar result for the Singapore football team at the South-east Asia (SEA) Games.
For the 11th time at the biennial Games, they lost in the semi-final to miss out on a chance to challenge for Singapore's first football gold.
Aide Iskandar's Under-23s were solid against their Thai counterparts, but the lack of a cutting edge up front, and a calamitous moment at the back, saw them bow out 1-0 Thursday night.
In the end, two of the three pillars whom Aide Iskandar had relied on so heavily in the tournament had their wires crossed when it mattered most, and it proved fatal.
After a good start that saw Hafiz Abu Sujad miss a one-on-one in the third minute, it all went to pieces 20 minutes later.
Under pressure from Thai striker Adisak Kraisorn, Singapore goalkeeper Izwan Mahbud and defender Safuwan Baharudin's both hesitated over a loose ball near their own penalty spot.
Swiss-born Under-17 World Cup winner Charyl Chappuis nipped in to knock the ball past Izwan, before Singapore right back Madhu Mohana bundled him over, leaving referee Kao Tung Fang with no choice but to point to the spot.
Praweenwat Boonyong expertly converted in what proved to be the winner to give Thailand a chance to add to their record 13 football gold medals tomorrow in the final against Indonesia, who deposed defending champions Malaysia 4-3 on penalties after they were tied 1-1 after extra time.
Thai coach Kiatisuk Senamuang conceded that Singapore were unlucky to lose.