Fast-improving Filipinas are building up to their maiden FIFA Women's World Cup but first Southeast Asian glory is at stake and a must-win clash against Vietnam on Tuesday.

The Vietnamese are reigning SEA Games champions and the only other team from the region going to the World Cup in Australia and New Zealand in July-August.

Ahead of the crunch encounter between the sides in the group stage of the SEA Games in Cambodia, Filipinas coach Alen Stajcic admitted Vietnam were the benchmark for his young team as they embark on a historic few months.

"Vietnam's been the best team in Southeast Asia, along with Thailand, for about 20 years now, 30 years," said the Australian.

"They're a good team, I actually love watching them play."

The Philippines are upsetting that duopoly.

It began at the Women's Asian Cup in early 2022, where they made the semi-finals, losing to continental giants South Korea but earning a historic first World Cup berth in the process.

They followed that up by taking bronze at the SEA Games a year ago in Vietnam, then won the regional AFF Women's Championship on home soil via a 4-0 semi-final win over Vietnam.

The Philippines are 49th in the FIFA rankings, the highest they have ever been.

Their rise has been driven in part by a push to recruit young players from the country's large diaspora, nurturing classy players such as goal threat Sarina Bolden and play-maker Quinley Quezada.

Their most recent XI –- average age just under 24 -– was composed entirely of players born in North America.

Their opening match of the SEA Games ended in a 1-0 loss to Myanmar, but they beat Malaysia 1-0 on Saturday, a towering header from Bolden the last meaningful touch of the game.

"Never give up, that's just always been my mentality. The game isn't over until that ref blows that final whistle," said the California-born Bolden, who top-scored at the AFF tournament with eight goals.

"I feel like this team has been through so much in the past 15-16 months. It doesn't matter what time of the game it is, just that Filipino resilience, we're never going to give up."

Their rise is clearly a problem for Vietnam, who have taken gold at the last three SEA Games and won their opening two matches this time round, led by goalscoring legend Huynh Nhu.

The sides face each other Tuesday in the final group game in Phnom Penh and the Philippines still need to make up the points to progress.

"It's a must-win game. We've beaten them once in our history — that was last year," said Stajcic.

"We can't leave anything in the locker room, we've got to leave it all on the pitch."

The Philippines will be rank outsiders at the World Cup but they are in an open-looking Group A alongside co-hosts New Zealand, Norway and Switzerland.