Defending men's football champions Thailand need a big win against Vietnam in their final group game on Thursday to be assured of a place in the semi-finals at the SEA Games.
After four games in the U23 tournament, Vietnam lead Group B on 12 points (with a goal difference of +13) followed by Indonesia (+11) and Thailand (+10) who each have nine points.
Assuming that Indonesia should have few problems against Laos in another game on Thursday, Thailand have to beat Vietnam by a margin of two goals to keep alive their hopes of winning the crown for the fourth time in a row.
Thailand coach Akira Nishino said on Wednesday he would urge his men to try to open the scoring against the Vietnamese as soon as possible.
"I can't assure you that we will score at least two goals but I will encourage my players to score the first goal as fast as possible. We could be under pressure if we can't score early on," said the Japanese coach.
"Vietnam's strong point is their teamwork -- they do not rely on a particular player. But every time Thailand meet Vietnam, our players are fired up."
Nishino has already met Vietnam coach Park Hang-Seo twice in recent World Cup qualifiers which ended in a scoreless draw on both occasions.
The young War Elephants have been less than convincing at Philippines 2019.
They lost 2-0 to Indonesia in their opening match and got a 2-0 win over Laos in their previous match thanks to substitute Suphanat Mueanta's late strikes.
South Korea's Park said: "We have to forget all the previous victories. It was in the past and we have to focus on the important game with Thailand.
"Of course, it will be the most difficult game for us but we have to get through it for the next round."
In Group A yesterday, the Philippines beat Timor Leste 6-1 and Cambodia defeated Malaysia 3-1.
Cambodia join group leaders Myanmar in the semi-finals after finishing ahead of the Philippines on goal difference.