Philip Greatwich broke a 2-all standoff with a header on an assist by Ali Borromeo in the 82nd minute then Emelio Caligdong booted in a short lob that sailed over Cambodian goalie Ouk Mic, ensuring the RP XI victory that kept it in contention for the medal play.
The Nationals take a four-day rest before going for a semifinals berth versus the Malaysians Tuesday in the same venue.
Egged on throughout the game by flag-waving, cheering hometown fans, the Nationals dished out a sterling game and overcame the Cambodians physical game in humbling the visiting team right before Cambodian Norodom Ranariddh.
The Cambodians bowed out of contention for the medals on their second loss following a 2-5 rout by the Malaysians Monday. The halftime ended at 1-all.
It took the Nationals only 15 minutes after the interval to break the standoff as Borromeo, playing sick with a bum stomach, towered above five Cambodian defenders inside the box for a follow-up header off a corner kick by James Younghusband.
Pok Chan Than scored from 21 yards on a defensive lapse by the RP team in the middle as Cambodia equalized at 2-all in the 76th minute.
With the match looking headed for a draw, the RP booters stepped up their game and converted two goals in the last eight minutes to avoid outright elimination in the biennial meet.
"Im very proud of the boys," said coach Aris Caslib as the RP XI scored its very first win ever over Cambodia.
Its also the Philippines first win in the SEAG since beating the Brunei side in the 1995 Chiang Mai Games.
"We cant ask for more from the boys. They gave their all in this game for flag and country," said Philippine football executive vice president Tony Chua.
Fil-Briton James Younghusband had his own goal to break the ice in the 11th minute but Borromeo proved to be the biggest hero on his goal, assist and intimidating presence in the contest.
"It feels great," said Borromeo amidst the din of the victory celebration.
RP goalie Louie Michael Casas also played a key role as he came away with a number of saves, the most crucial of which being the attack launched by the Cambodians just after tying the count at 2-all.
Caslib said they had their mistakes but hes hopeful they can correct these in the next three days prior to their virtual knockout match with Malaysia.