MANILA, Philippines – (UPDATED) In a preview of their showdown in the Southeast Asian Games next week, Team Philippines and Vietnam engaged in a heated volleyball battle in the 19th AVC Asian Senior Women's Volleyball Championship in Biñan, Laguna on Monday evening.

When the dust settled, the Filipinas pulled off a stunning 27-25, 26-24, 17-25, 25-23 victory over their regional rivals to secure the third seed in Pool E, and set up a quarterfinals showdown with powerhouse Thailand.

Alyssa Valdez had her highest scoring game of the tournament, tallying 20 points while proving to be a clutch performer anew for the Philippines. Jaja Santiago added 19 points, while Dawn Macandili turned in a superb defensive job with 19 excellent digs and 12 successful receptions.

Also coming through with a solid performance was Abigail Maraño, who had 11 points. Maika Ortiz contributed eight markers, and had the unenviable job of checking Vietnam's towering Thuy Tran Thi Thanh throughout the game.

"Ang gusto lang talaga namin in today's game is to really show Vietnam that we've improved on everything – lahat, from defense to offense," said Valdez. "At saka 'yung teamwork namin talaga, I think 'yun ang focus namin."

"It's not about the points, it's not about winning. It's about the teamwork, the jelling, and the chemistry of the team," she added. "Today, we really wanted to show everyone that we're inspired to play for each other."

• Koreans stay unscathed, clinch quarters top seed in Pool E

Matched up against the silver medalist in the 2015 SEA Games, the Philippines found itself trailing 19-23 in the opening set, but the net defense of Ortiz on Thuy, plus a clutch hit by Valdez allowed the Filipinas to catch up, 24-all. Valdez then came through with an ace in the final rally to complete the comeback in Set 1.

Valdez wins set 1 with an ace! #AVCWomensSCH pic.twitter.com/UcUTZ5qD7B

— ABS-CBN Sports (@abscbnsports) August 14, 2017

It was the same story in Set 2, as the Philippines again trailed 21-24. But back-to-back hits by Valdez and Santiago, combined with a hitting error from Vietnam's captain Nguyen Thi Ngoc Hoa, tied the frame at 24-all.

Again, Valdez came up big. The former Ateneo de Manila University stalwart fired up two consecutive aces, putting the Philippines on top, 2-0.

Back-to-back aces for @AlyssaValdez2 to win the set! Again! #AVCWomensSCH pic.twitter.com/efSsNIFdMZ

— ABS-CBN Sports (@abscbnsports) August 14, 2017

Vietnam then took advantage of the Philippines' lackluster play in the third set to seize a 25-17 win, but the Filipinas came back with renewed energy in the fourth frame, building a 10-5 lead off a huge kill by Santiago.

They nursed that lead most of the way, and reached match point, 24-20, thanks to Aiza Maizo-Pontillas.

Aiza Maizo-Pontillas VICIOUS cut shot in the clutch! #AVCWomensSCH pic.twitter.com/Ny1iyqbi80

— ABS-CBN Sports (@abscbnsports) August 14, 2017

However, Vietnam also showed that it was capable of a comeback. Both Ortiz and Valdez found themselves blocked, before an ace by setter Nguyen Linh Chi made it a one-point game, 23-24.

But playing on their home floor, in front of a passionate crowd, the Philippines would not be denied. Macandili came up with a fantastic first ball in the next rally, and Kim Fajardo set up a combination play that allowed Valdez to hammer the ball almost unimpeded.

.@kimfajardo9 to @AlyssaValdez2 FOR THE WIN! #AVCWomensSCH pic.twitter.com/o0sgVIzDal

— ABS-CBN Sports (@abscbnsports) August 14, 2017

"Lahat kami, pinapakita namin na lumalaban kami, binibigay namin ang best namin para manalo kami ngayong araw na ito," said Ortiz after the game.

Thuy still finished with 16 points, but she did most of her damage in the third set and was held in check most of the way.

Because of their loss to the Philippines, Vietnam will face Japan in the quarterfinals. The Japanese earlier defeated Thailand in four sets.

The Philippines and Vietnam will meet again in the SEA Games on August 25.

(For more sports coverage, visit the ABS-CBN Sports website.)