Australian Sam Stosur has won her way through the second round of the US Open with a 7-5, 6-7 (4-7), 6-1 win over Italian Camila Giorgi.

After two tight sets, which lasted almost two hours, Stosur comfortably prevailed in the third to set up a second round encounter with China's Zhang Shuai.

Girorgi troubled Stosur early, managing the bulk of her 34 winners in the opening two sets. However, the Italian ultimately came unstuck due to 45 unforced errors and 14 double faults.

"It was really important for me to hold my ground and stay strong and really whenever I had my chance and an opportunity to take advantage of that," Stosur said post match.

"So it's really pleasing that I was able to do that the whole match and even after the disappointment of losing the tiebreak to start the third strong and get a bit of a lead.

"Then things started going in my favour."

Meanwhile, fellow Aussie Daria Gavrilova fell in the first round to Lucie Safarova, 6-4, 6-4.