Two-time runner-up Victoria Azarenka has reached her fourth US Open quarter-final with a 6-3 6-4 win over Varvara Lepchenko of the United States.
Former world number one Azarenka, the 20th seed, will face either Romanian second seed Simona Halep or Sabine Lisicki, the 24th-seeded German, for a place in the semi-finals.
The Belarusian, whose season has been stalled by a left thigh strain, appeared on Arthur Ashe Stadium on Monday with both biceps tightly strapped.
“It’s a little embarrassing. I have blisters from my shirts rubbing against my arms so I needed the bandages,” said Azarenka, the runner-up to Serena Williams in 2012 and 2013.
“It looks weird but I did what I have to do.”
Lepchenko, who was bidding to become the first American woman not called Williams to make the last-eight since 2009, was broken in the third and ninth games of the opening set.
She rallied to edge ahead in the first game of the second but handed the break straight back to the 26-year-old Azarenka.
The Belarus star carved another break for 5-3 before faltering when she served for the match.
But she secured victory in the next game on her first match point when left-handed Lepchenko went wide.
“I felt at 5-3 that I never went for my shots, she didn’t give me much rhythm,” she said.
“But I told myself to be aggressive and go for it.”
Halep will bid to reach her maiden US Open quarter-final and be the first Romanian to make the last eight since Irina Spirlea went to the 1997 semi-finals.
Lisicki, the 2013 Wimbledon runner-up, has never made the last eight in New York.
Halep, who has a 3-1 career record over Lisicki, has hardly been tested at the tournament, conceding just 14 games in three rounds.
Czech fifth seed Petra Kvitova has had an even easier path through the first week, dropping just 12 games.
The two-time Wimbledon champion takes on British qualifier Johanna Konta, the world number 97.
Victory would make Halep the first Czech in the quarter-finals since Daja Bedanova in 2001.
Konta will be Kvitova’s third opponent in four matches ranked outside the top 90.
The 24-year-old Konta hopes to become the first British woman in the last-eight since Jo Durie in 1983.
The winner of that tie will face either Australia’s 22nd seed Samantha Stosur, the 2011 champion, or Italy’s Flavia Pennetta, the 26th seed.
Pennetta has established an iron-grip on the Australian, winning all of their six career meetings.
The 33-year-old Italian is looking to reach the quarter-finals for the sixth time.
Stosur, 31, boasts the accomplishment of being the last woman to defeat Serena Williams in New York in 2011.
Serena features on Tuesday when the quarter-finals get underway, facing sister Venus for the 27th time as she continues her bid to complete the calendar Grand Slam.
Tuesday’s other quarter-final sees France’s Kristina Mladenovic tackle fellow unseeded player Roberta Vinci, who reached the last-eight when Eugenie Bouchard pulled out of the tournament with a concussion suffered in a locker room fall.