Argentina and the USA were heading the Group B standings with seven points each from three matches after Argentina outplayed Germany 3-0 and the USA posted a runaway 5-0 victory over China.
South Africa scored their first win in three outings when they handed down shock 4-1 defeat to 2012 Olympic bronze medalists England, who have now suffered three consecutive defeats.
Stamping their authority against the German defence, the Argentine girls surged ahead with a fourth-minute penalty corner conversion by Silvina D'Elia.
Noel Barrionuevo then converted a penalty corner in the 32nd minute and Carla Rebecchi scored in open play in the 45th minute to shatter the German hopes.
In the other match of the group, Katie O'Donnell scored three goals for the USA, who finished at the bottom of the 12-team competition at the 2012 Olympics.
She opened the scoring with an open play strike in the fourth minute. Michelle Vittese increased the American lead in the 10th minute before O'Donnell got back into the goal-scoring act with successive strikes in the 30th and 63rd minutes.
Kelsey Kolojejchick rounded off the America's tally three minutes from the hooter.
China and Germany had four points each from their previous two matches, but slipped a notch behind by failing to add any points today.
Four South African girls made an entry each on the score-sheet today as Kathleen Taylor, Sulette Damons, Shelley Russell and Dirkie Chamberlain shot on target to make it 4-0 before England pulled one back through Nicola White.


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