Defending champion Japan took an early lead in its group at the Women's Asian Cup with a 4-0 shutout of Vietnam on Saturday.
Kumi Yokoyama opened the scoring in the third minute at King Abdullah II Stadium, and later goals by Emi Nakajima, Mana Iwabuchi, and Mina Tanaka earned Nadeshiko Japan three points.
"It's a good start. If I'm being greedy, I wanted a few more goals, but four is enough of a harvest," manager Asako Takakura said. "But there's still more to go. We'll give it everything (in the next match)."
In the other Group B match, Australia and South Korea held each other to a 1-1 draw.
The Women's Asian Cup serves as the final stage of Asian qualification for the 2019 World Cup in France, with the top five teams qualifying.
Japan faces South Korea on Tuesday.