Sam Stosur crushed Sara Errani of Italy 6-2, 6-3 to reach the fourth round of the US Open tennis tournament here on Friday.

The Australian, French Open runner-up, played out power and aggression, smacking 37 winners and landed seven aces to dispatch Italy's Errani, booking a date on Sunday with Russian 12th seed Elena Dementieva.

"I'm really happy with that win," Stosur said. "Since my first round I think I've played two really good matches now. Yeah, couldn't ask for much more."

Errani stretched Stosur to a third-set tiebreaker only last week in Cincinnati, and even had four match points to cause a boilover, but the plucky Italian conceded the Australian found another level on Friday.

Errani, the world number 37 admitted Stosur's raw power and lethal forehand had her on the back foot and under pressure.

"She served very good and I couldn't go to her backhand, so it was difficult. And with that forehand, she can do what she wants," Errani said.

After trading early service breaks, Stosur exploded to life to reel off four straight games to take the first set in 33 minutes.

The second set was more competitive but, even when Errani grabbed another break to nudge ahead 3-2, Stosur continued to dictate.

The world number six again nailed another four consecutive games to close out the contest, sealing a backhand winner down the line on match point to advance after one hour, 20 minutes.

Stosur racked up 16 break points against the Italian, converting five, while Errani only managed two on the Australian's big serve.

Stosur trails Dementieva 4-1 in their career series but said she couldn't be happier with her game as she enters the second week at Flushing Meadows for the first time in seven attempts.

"There's nothing that I'm going to have to go out and work on or think that I need to drastically improve," she said.

"Just keep everything and the usual things, serve well, return well. If you can do those, then I think you've got a good chance."

Sam Stosur crushed Sara Errani of Italy 6-2, 6-3 to reach the fourth round of the US Open tennis tournament here on Friday.

The Australian, French Open runner-up, played out power and aggression, smacking 37 winners and landed seven aces to dispatch Italy's Errani, booking a date on Sunday with Russian 12th seed Elena Dementieva.

"I'm really happy with that win," Stosur said. "Since my first round I think I've played two really good matches now. Yeah, couldn't ask for much more."

Errani stretched Stosur to a third-set tiebreaker only last week in Cincinnati, and even had four match points to cause a boilover, but the plucky Italian conceded the Australian found another level on Friday.

Errani, the world number 37 admitted Stosur's raw power and lethal forehand had her on the back foot and under pressure.

"She served very good and I couldn't go to her backhand, so it was difficult. And with that forehand, she can do what she wants," Errani said.

After trading early service breaks, Stosur exploded to life to reel off four straight games to take the first set in 33 minutes.

The second set was more competitive but, even when Errani grabbed another break to nudge ahead 3-2, Stosur continued to dictate.

The world number six again nailed another four consecutive games to close out the contest, sealing a backhand winner down the line on match point to advance after one hour, 20 minutes.

Stosur racked up 16 break points against the Italian, converting five, while Errani only managed two on the Australian's big serve.

Stosur trails Dementieva 4-1 in their career series but said she couldn't be happier with her game as she enters the second week at Flushing Meadows for the first time in seven attempts.

"There's nothing that I'm going to have to go out and work on or think that I need to drastically improve," she said.

"Just keep everything and the usual things, serve well, return well. If you can do those, then I think you've got a good chance."