Thailand are the record four-time champions of the ASEAN Women's Championship. Vietnam are not far behind with three titles of their own.
Both, however, had to watch on in disappointment three years ago as upstarts Philippines usurped the traditional favourites to be crowned the new queens of Southeast Asian football.
And in some style too, with the Filipinas seeing off Vietnam 4-0 in the semifinals before claiming their first crown with a comfortable 3-0 victory over the Thais in the decider.
Neither will look back on that tournament fondly but with the latest edition -- officially known as the ASEAN MSIG Serenity Cup 2025 -- kicking off on Wednesday, the two perennial contenders wasted no time in showing they are back with a vengeance.
Thailand got the Group A action underway earlier in the evening and flexed their muscles with a 7-0 win over Indonesia.
They were leading by five goals at halftime and, after Indonesia produced more resistance early on in the second half, would add two more in as many minutes to complete the emphatic rout.
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What made the result all the more impressive was the sheer precociousness in their team, with just one member from their 2022 squad returning in Chatchawan Rodthong, who unsurprisingly has been chosen to lead the team.
Whether by design or pure coincidence, the Thais will be undergoing a period of rejuvenation at this tournament.
They will not be able to rely on the likes of Taneekarn Dangda, Sunisa Srangthaisong and Warunee Phetwiset, who all played pivotal roles in a glorious era which included multiple regional titles, creditable finishes at the AFC Women's Asian Cup and even appearances at back-to-back FIFA Women's World Cups in 2015 and 2019.
If Wednesday's opening display is anything to go by, there is plenty of talent waiting in the wings.
Kanjanathat Phomsri, Madison Casteen and Janista Jinantuya formed an exciting front three that combined for four of Thailand's five first-half goals.
Kanjanathat is the oldest at 22. Only 17, Casteen is a prospect that Thailand has been closely watching as she learns her craft in the women's football powerhouse nation that is America.
Another 17-year-old in Pinyaphat Klinkai also showed maturity beyond her years in the heart of defence and even snuck forward to score Thailand's sixth, while Pichayatida Manowang -- a year older -- was a dynamo in the heart of midfield.
No one in the entire squad is over the age of 23.
Perhaps when tougher opponents stand before them, Thailand's precociousness will really be called into question.
When that time comes, it will also provide their precocious talents to rise to the occasion.
Such a challenge could come as soon as the end of the group stage, when they are due to meet tournament hosts Vietnam.
Unlike the Thais, Vietnam will have no issue with a lack of experience.
In a display brimming with confidence, Vietnam followed Thailand's triumph with a 6-0 triumph over Cambodia.
They were even more brutal right from the beginning, racing to a 4-0 lead inside the opening 17 minutes to leave Cambodia absolutely shellshocked.
With focal point in attack Phạm Hải Yến flanked by the creative Nguyễn Thị Bích Thùy and energetic Nguyễn Thị Vạn, the Vietnamese ran circles around the Cambodia defence.
Trần Thị Duyên and Ngân Thị Vạn Sự never stopped providing support down the wings, while Thái Thị Thảo and Dương Thị Vân dominated the midfield.
Vietnam's starting XI combined for a staggering 585 caps. Remarkably, this did not even include the two centurions in their squad
With their entire footballing philosophy and identity now seemingly centred on a 3-4-3 system, across men's, women's and age-group levels, there is less opportunity now for two spearheads to coexist.
Of course, players' versatility does lead to occasions when more than one main striker can be on the field at one time.
Still, how wonderful must it be for Vietnam coach Mai Đức Chung to have the option of replacing Hải Yến, who has 49 goals from her previous 88 caps, at halftime with captain Huỳnh Như -- their all-time top scorer with 68 goals from 109 caps who also was the first Vietnamese female footballer to play in Europe.
And while she did not take to the field on Wednesday, Nguyễn Thị Tuyết Dung -- Vietnam's record appearance maker and third-highest scorer with 51 goals -- is another proven campaigner ready to be called upon.
Based on their opening displays, Thailand and Vietnam should now be confident in their prospects of finishing in Group A's top two and advancing to the semis. That would simply be a pass mark given their history at the tournament.
They will now wait and see if similar statements are issued in Group B, where Philippines and Australia U-23 loom as the frontrunners.
For now, Thailand and Vietnam could not have done more to show they mean business following their disappointment from three years ago.