Yuka Momiki made it two goals in two games but Samantha Kerr scored a first-half hat trick Sunday as Australia maintained its perfect record with a 4-2 victory over Japan in the Tournament of Nations.

On the second game day of the four-team women's international soccer tournament, Japan forward Mina Tanaka opened the scoring six minutes in, but Australia pulled even in the 11th minute when Kerr found the back of the net on a cross from Hayley Raso.

Kerr netted her second in the 16th at Qualcomm Stadium and completed the hat trick following a break out in the 43rd, scoring on her second attempt after the first was parried.

Momiki, who had a goal in the opening 1-1 draw against Brazil on Thursday, nailed a left-footed shot into the bottom right corner to spark a late challenge minutes before the final whistle, but it was no more than a consolation as Australia had secured a fourth goal on a 62nd-minute penalty.

"They beat us too easily and it's upsetting. We gave away the ball too many times and were our own worst enemy. Our defenders pushing up created too much space for their attack," said Japan coach Asako Takakura.

In their final game of the round-robin tournament, Japan plays the United States on Thursday. After a 1-0 defeat to Australia, the U.S. ranks second with a 1-1 record while Japan is ranked last, falling behind Brazil on goal difference, each team with one loss and one draw.