For the first time in 16 years, Australia will be represented by both a women's and men's football team, after the Matildas secured their fourth Olympic berth this week and the Olyroos qualified for the first time since Athens 2004.
Australia confirmed their fourth Olympics appearance with a 2-1 away triumph over the Southeast Asian nation in Wednesday evening's away leg at the Cẩm Phả Stadium, which was played without spectators due to coronavirus precautions.
Ante Milicic made two changes from the eleven which beat The Golden Girls 5-0 in Newcastle five days earlier.
Elise Kellond-Knight replaced Tameka Yallop at the base of midfield, while Kyah Simon dropped to the bench for Hayley Raso, who was deployed on the right of a front three.
As a result, Chloe Logarzo stepped back into the midfield.
A power failure within the first minute stopped play for 20 minutes but it wasn't long after the stadium was lit up that the Matildas' 5-0 goal buffer was built upon, thanks to first-half strikes from Sam Kerr and Hayley Raso.
Kerr - who minutes earlier had hit the underside of the post after she was slipped through on goal by Foord - opened the scoring after knocking Steph Catley's cross past Vietnam number one Tran Thi Kim Thanh with a tidy volleyed finish.
It was a goal that moved the captain into outright second on the all-time Matildas scoring charts - the Chelsea forward's 42nd effort in 88 games.
Australia began to turn the screw and having broken the deadlock herself, Kerr turned provider as Raso scored her sixth international goal and put Australia 2-0 up on 27 minutes.
Huynh Nhu scored Vietnam's first-ever goal against Australia in the second half at the Cẩm Phả Stadium.
Congratulations to @TheMatildas who have just booked their ticket to @Tokyo2020 🥳🙌🏽— AUS Olympic Team (@AUSOlympicTeam) March 11, 2020
And for the first time in 16 years, 🇦🇺 will have both a women’s and men’s football team competing at an Olympic Games 💚💛#TokyoTogether #Tokyo2020 https://t.co/fDlXUgI3OC
Australia are now one of three AFC representatives to feature at the global football showpiece, to be played between July and August this year.
Korea Republic will battle with China PR for the other AFC spot, with Japan having already qualified as tournament hosts.
The Matildas will join the Olyroos who secured their Tokyo 2020 ticket after winning the third-place play-off at the AFC U-23 Championship in January.