Cambodia went down to an 88th minute Myanmar winner in their third Philippines 2019 Southeast Asia (Sea) Games football match at the Binan Stadium on Monday night.
With the sides going into the match joint top of Group A, victory would have put the Angkor Warriors on the brink of reaching the the semi-finals.
However, it was Myanmar who qualified for the medal round, with Cambodia needing victory over Malaysia in their match on Wednesday at the Rizal Memorial Stadium in Manila to join them.
Cambodia went ahead in the 23rd minute when forward Sin Sophanat reacted quickest to tap home after Myanmar keeper Sann Sat Naing spilled a long-range effort from Mao Piseth.
But their joy was to prove short-lived when four minutes later an unmarked Lwin Moe Aung was found with a neat pass to shoot past Cambodian keeper Hul Kimhuy from the edge of the area.
The sides went into the interval all-square, and it was Myanmar who came out the livelier, bringing the game to Cambodia in the second half.
Their pressure paid off in the 88th minute.
Aung bagged his brace when his shot from a tight angle at the edge of the box was palmed into the goal by Hul, who got back desperately to almost claw the ball out before it crossed the line.
Cambodia, Malaysia and the Philippines are all tied on four points going into their final matches.
With a superior goal difference of four over the Philippines, a win against Malaysia should earn Cambodia a place in the semi-finals if group whipping boys Timor-Leste can keep the score down against the hosts.
However, with Timor-Leste having lost all three of their games so far, shipping 11 goals, including five against Cambodia, a draw or loss to Malaysia on Wednesday will likely see the Warriors on their way home.
Malaysia have drawn 1-1 with Myanmar and lost 1-0 to the Philippines, while beating Timor Leste 4-0.