Holders Japan and South Korea joined Australia in the last eight of the Women's Asian Cup, and now meet to decide which is likely to face the Matildas.
Japan and South Korea have overcome obdurate but outgunned opponents to take the automatic qualifying places in group C of the Women's Asian Cup, joining Australia and China in the last eight.
Holders Japan scored three goals in a 20-minute burst either side of the interval to beat Vietnam 3-0, following 4-0 wins against the same opponents in the 2014 and 2018 tournaments. Yui Narumiya scored twice, sandwiching a rare goal from captain Saki Kumagai. It was the Bayern Munich player's second goal in 121 internationals.
South Korea beat Myanmar 12-0 in the 2014 competition but went goalless against them for 50 minutes before English-based duo Lee Geum-min and Ji So-yun scored in a 2-0 win.
Japan and South Korea now meet on Thursday to determine who tops the group, with the runners-up likely to face Australia in the quarter-finals.
The Matildas ensured they are likely to top group B with a 4-0 win over a Philippines side managed by former coach Alen Stajcic. After a frustrating first half Sam Kerr made the breakthrough in the 51st minute. Dominique Randle's own goal two minutes later was followed by further scores by Emily van Egmond and Mary Fowler.
Australia will top the group unless they lose on Thursday to Thailand, who beat Indonesia 4-0 with a hat-trick from Kanyanat Chetthabutr.
The Thais changed all 11 players from the team beaten 1-0 by Philippines in their opening game, but still had enough to dominate an Indonesian side beaten 18-0 by Australia.
China qualified for the last eight on Sunday, Tuesday is a rest day.
The top two in each group will be joined in the knock-out rounds by the two best third-place finishers.