Daria Gavrilova and Anastasia Rodionova have continued Australia's promising start to the claycourt season to join 2010 champion Samantha Stosur in the third round of the Charleston Open.
In a huge confidence-booster, Rodionova upended former French Open runner-up Sara Errani 6-2 6-2 in only her second main-draw match at WTA level in almost a year.
Errani infamously shattered Stosur's hopes of a second Roland Garros final appearance in 2012 with a shock semi-final win over the former US Open champion.
Gavrilova, the ninth seed in South Carolina, won 6-3 6-1 over Alison Riske of the US.
Stosur plays Irina Camelia-Begu next for a place in the fourth round after crushing former world No.1 Jelena Jankovic 6-1 6-3 in a rematch of their 2010 French Open semi-final.
In other matches, German Laura Siegemund upset Venus Williams 6-4 6-7 (7-3) 7-5 to win her second three-set match in three days and move on to the third round.
Russian Daria Kasatkina outlasted Puerto Rican Olympic champion Monica Puig 6-0 6-7 (7-3) 6-2.
Kasatkina, a one-time French Open junior champion who came close to making the semi-finals here last year, will face good friend and doubles partner Gavrilova next.
Teenage qualifier Fanny Stollar caused a major upset with a 7-6 (9-7) 7-6 (7-3) win over fourth seed Elena Vesnina.
There were also straight sets victories for Naomi Osaka, Kiki Bertens, Mirjana Lucic-Baroni, Ons Jabeur and Anastasija Sevastova.
PA