Yui Narumiya struck a goal in each half Monday as two-time defending champions Japan booked their place in the quarterfinals of the Women's Asian Cup in India with a 3-0 win over Vietnam.
With a maximum six points from their two matches, Nadeshiko Japan are guaranteed to advance as one of Group C's top two teams to the knockout stage of the tournament, which doubles as a qualifier for next year's World Cup.
INAC Kobe Leonessa midfielder Narumiya found the net in the 38th and 58th minutes at the Shree Shiv Chhatrapati Sports Complex in Pune, bookending a goal from captain Saki Kumagai just after halftime.
Following Japan's opening 5-0 demolition of Myanmar, manager Futoshi Ikeda retained only Kumagai, Risa Shimizu and Mina Tanaka in his starting lineup.
Narumiya opened the scoring from close range, converting after Vietnam keeper Tran Thi Kim Thanh spilled a shot from defender Hana Takahashi.
Bayern Munich star Kumagai doubled the lead five minutes into the second half when she was first to react after Tanaka's header hit the woodwork.
The captain was instrumental in the third goal, redirecting a corner kick to the unmarked Narumiya, who fired home from the middle of the area.
Japan will play Thursday against South Korea, the other undefeated Group C side, with top spot in the group at stake.
"I'm glad we were able to score from a set piece we worked on in training, (but) our combinations still need some work," Ikeda said.
"(South Korea) will be a more difficult match."
In a massive blow to the tournament, hosts India have had their remaining matches canceled after being unable to field a team against Group A opponents Taiwan due to a COVID-19 outbreak among players.
All matches involving India have been declared null and void in accordance with Asian Football Confederation rules specially drafted for hosting competitions during the pandemic.