Nikki Hudson, Sarah Taylor and Angie Skirving all got on the scoresheet for a second straight victory in Madrid.

Australia coach Frank Murray said: "We had seen the USA play in lead up games and we knew how they could play. We are very pleased with a 3-1 win."

Earlier Korea missed the chance to top the group when they drew 0-0 against South Africa.

Korea often dominated, but Jen Wilson, playing her 100th match for South Africa, was inspirational as her team's under-siege defence held firm.

Our defence was outstanding but we gave the ball away too easily South Africa coach Jenny King after a 0-0 draw with Korea

South Africa coach Jenny King was happy to claim a point after her team's opening 1-0 loss against Australia.

"I'm pleased with our first point although no goals in two games is a concern," she said.

"Our defence was outstanding but we gave the ball away too easily."

Korea, who began the tournament with a 2-1 win against Japan, faded in hot conditions and had to be content with a draw.

Meanwhile, Argentina held off a late fightback from Japan to secure a 3-2 in the other Pool B game.

Argentina are second in the standings behind Australia, who prevailed in a high-tempo game against USA.

Sarah Taylor's deflected shot put the Australians ahead before Kelly Doton hammered in the equaliser.

Hudson then scored from a diving tomahawk shot just before half time and Skirving grabbed a corner goal with 13 minutes remaining.