The Hockeyroos have sealed their place in the FIH Women's World Cup quarter-finals by recording another win in Spain.

The world No.3 saw off South Africa 2-1 in their final Pool D match to set up a last-eight clash next Wednesday (Thursday AEST) with the winner of the contest between the team that finishes second in Pool C and third in Pool B.

First-half goals from Penny Squibb and Rosie Malone sealed the Hockeyroos' third win from as many matches in what was Mariah Williams' 100th international appearance.

"I'm really proud to reach 100 games ... it has been a long time coming," two-time Olympian Williams said.

"I've had my share of ups and downs with injuries along the way, but I stuck to it and couldn't have asked for anything better than to achieve it in NAIDOC Week wearing the Indigenous kit."

Needing a win or draw to automatically progress to the last eight, the Hockeyroos took the lead in the eighth minute.

After Hockeyroos goalkeeper Jocelyn Bartram had kept out an early penalty corner, Squibb capitalised on Australia's first penalty corner as the South Africa goalkeeper was unable to keep the defender's drag flick from finding the back of the net.

The reply was swift from the world No.16 and Lilian du Plessis sent a powerful drag flick of her own past Bartram five minutes later to level the scores. It was the first goal the Hockeyroos had conceded in the tournament after previous 2-0 victories over Japan and Belgium.

On 24 minutes, Malone popped to score her second goal of the tournament after Maddy Fitzpatrick's well directed drag flick spilled to Malone who had time to fire home.

Australia had the chance to extend their advantage early in the third quarter after 18-year-old forward, and player of the match, Hannah Cullum-Sanders was impeded in the attacking circle for a penalty stroke.

But looking to cap off her milestone game with a goal, Williams sent her stroke low and wide of the target.