New York: Sara Errani`s softly-softly approach paid off Sunday as she booked her US Open quarter-final berth with a 6-3, 2-6, 6-0 victory over Mirjana Lucic-Baroni.
The 13th seeded Italian was the first woman into the last eight, where she could find former champion Maria Sharapova or Caroline Wozniacki waiting for her.
Sharapova and Wozniacki, both former world number ones, clashed later, the Russian trying to extend her dominance over the Dane she has beaten in five of seven prior encounters.
Yet another former world number one, ninth-seeded Serb Jelena Jankovic, took on Swiss 17-year-old Belinda Bencic, and 14th-seeded Czech Lucie Safarova tried to stop the run of unseeded Chinese Peng Shuai.
Peng and Bencic were key contributors in the spate of upsets that saw five of the top eight women eliminated before the fourth round.
Peng ousted fourth-seeded Pole Agnieszka Radwanska in the second round and Bencic dispatched sixth-seeded German Angelique Kerber in the third.
Bencic, coached by Martina Hingis` mother Melanie Molitor, is trying to become the youngest US Open quarter-finalist since Hingis won the 1997 title at the age of 16.
Lucic-Baroni, a 32-year-old qualifier ranked 121 in the world, accounted for the third-round exit of world number two Simona Halep.
But the Croatian, a teen sensation in the 1990s whose career was derailed by the trauma of an abusive father, financial troubles and injury, couldn`t find a way past the metronomic Errani.
The Italian played it safe on a windy Arthur Ashe Stadium court, coming up with just four outright winners to the 46 of Lucic-Baroni -- but also committing only nine unforced errors to the 69 of her opponent.
In the first set, Errani put 100 percent of her first serves in play. Asked how she managed that on such a windy day, Errani said she couldn`t afford not to.
"I serve slowly, so I have to put mine in," she said.
Errani reached the French Open final in 2012, a career-best year that saw her win four singles titles and crack the top 10 in the world rankings.
She reached the summit of the doubles rankings that year as she claimed eight titles with Roberta Vinci, including the US Open doubles crown.
She and Vinci completed a career doubles Grand Slam at Wimbledon this year, but Errani will be free to focus on her singles campaign this week -- she and Vinci were eliminated in doubles in the second round in New York.