Australia's Grace Stewart, right, tries to score past United States' goalkeeper Jackie Briggs and teammate Michelle Kasold. (AP Photo/Dario Lopez-Mills)

RIO DE JANEIRO -- United States women’s field hockey goalie Jackie Briggs’ performance at the Olympics has awed teammate Caitlin van Sickle.

In wins over No. 2 Argentina and No. 3 Australia, Briggs faced a combined 28 shots and allowed just two goals -- one in each of the 2-1 victories.

“Amazing,” van Sickle said of the 28-year-old from Robesonia, Pa. “She’s a ninja. She keeps us in it, and we have our full confidence in her.”

Briggs' excellent play has propelled the fifth-ranked Americans to the top of Group B.

United States coach Craig Parnham said after Saturday’s win over Argentina that his goalie would need to be “on song” -- or at her best -- for the Americans to be successful the rest of the tournament. She came through on Monday, as Australia failed on all four of its penalty corners against her.