Barty had a titanic fight to move through to the Round of 16 in the US Open doubles, with her and partner Victoria Azarenka toplling Anna Spears and Nadiia Kichenok 3-6, 6-3, 7-6 (12-10).

The endurance contest seemed to take it out of Barty, and she easily slumped to world number 18 Wang Qiang in the singles' fourth round.

The pair now face the all-American pairing of Caty McNally and Cori Gauff, who despite their relative unknown will have a significant home court advantage and should pull a large crowd to face the Grand Slam champions.

Stosur and Rajeev Ram, the third seeds in the mixed doubles, also moved through to their second round and will face seasoned campaigners Kirsten Flipkens and Edouard Roger-Vasselin for a spot in the quarter finals.

Flipkens and Roger-Vasselin will be much tougher opponents than the duo's first round matchup, with both the Belgian and French players garnering a fair amount of success on the singles court and even greater in doubles.

The last remaining hope for Aussie women at the US Open (there are also two males taking part in the second round of the US Open boy's singles) is Annerly Poulos.

The 16-year-old girl of Greek and Maori heritage is the only Aussie contesting the first round of the US Open girl's singles and is ranked 47th on the ITF junior's tour.

She has a good draw however, taking on Filipino qualifier Alexandra Eala for a chance to face aptly-named eighth seeded American junior Hurricane Tyler Black in the second round.