NEW YORK: Caroline Wozniacki upset French Open champion Maria Sharapova in a groundstroke marathon to reach the US Open quarter-finals, while Gilles Simon registered the first big surprise in the men's draw on Sunday.
France's Simon, the 26th seed, defeated Spanish fourth seed David Ferrer, who became the first top 10 men's seed to be shown the exit when he fell 6-3 3-6 6-1 6-3 in the third round on a hot, humid day at Flushing Meadows.
But it was the women's fourth-round match-up between Sharapova and Wozniacki that stole the show at the US National Tennis Center.
The 10th-seeded Wozniacki, who ruled as world number one for 67 weeks but never won a grand slam crown, showed great grit in battling to a 6-4 2-6 6-2 victory over fifth seed Sharapova in a two hour 37 minute slugfest in sweltering conditions.
Victory sent the 24-year-old Dane to her first grand slam quarter-final since the 2012 Australian Open, a stretch of 11 events, with Italy's Sara Errani awaiting as her opponent.
Errani, the 13th seed, ended the rejuvenated run of 32-year-old Mirjana Lucic-Baroni of Croatia 6-3 2-6 6-0 in their fourth-round match.
Wozniacki used her stellar footwork and notable fitness to stymie Sharapova, who was forced into a slew of 20-stroke rallies that fit the Dane's game plan.
Wozniacki, who is in training to run this year's New York City Marathon, won the hard-fought first set by breaking Sharapova in the last game.
Sharapova dominated the second set to level the match at one set apiece when officials gave the players a 10-minute break invoking the heat rule.
The critical break in the third set came after a spectacular point when Wozniacki three times raced across the baseline to retrieve in miraculous fashion, with Sharapova netting a backhand volley on the last shot to fall beind 3-1.
A slew of upsets on Wozniacki's half of the draw make her possible passage to the final a bit less daunting with second seed Simona Halep, foruth seed Agnieszka Radwanska and sixth seed Angelique Kerber already removed.
It was an emotional triumph for Wozniacki, who has had a tumultuous year in her personal life.
Wozniacki's slide down the rankings starting a couple of years ago coincided with her dating and subsequent engagement with major golf champion Rory McIlroy.
This year the Northern Irish golfer called off their wedding days after invitations were mailed.
"It means so much to me," she told the Arthur Ashe Stadium crowd. "It's been a bit up and down year for me. To win against a champion like Maria is an unbelievable feeling."
Asked if she would skip any additional training for November's marathon run, Wozniacki said: "I think this afternoon I'm just going to take a nice bath, have a massage and chill. And I think I deserve to have some chocolate or something."