With a spot in the biggest match of her tennis career at stake, Lesia Tsurenko never gave up.
Trailing by a set and a break and struggling with the effects of another sweltering day in the New York sun, the 29-year-old Ukrainian advanced to her first Grand Slam quarterfinal with a 6-7, 7-5, 6-2 win over Czech teenager Marketa Vondrousova on Monday.
In nearly two-and-a-half hours on the Grandstand court, the Ukrainian let a 4-1 lead slip away in the first set, and trailed, 7-6, 2-0, before engineering a stunning comeback, fittingly, on Labor Day.
"At some point, I just thought that it's over for me," she confessed after the match. "But then at the beginning of the second set, I could feel like a breeze, like a little wind, and it was cooler. Then I saw the shade, and I thought, 'Okay, I will try.' I give myself some hope.
"I'm proud of myself. I didn't expect that. As a tennis player, I know that we play in different type of conditions. Sometimes it goes like this. You need to survive."
Known as a bit of a late bloomer on the WTA tour – she didn't even turn professional until the age of 18 – Tsurenko reached a career-high ranking of world No. 29 last year.
Her backhand, one of the tour's best, has always been a weapon. In recent years, however, her right-handed groundstroke has become more dangerous.
"I changed the grip [on my forehand]. I did it with my ex-coach [Dimitry Brichek]. We actually worked mostly on my forehand because I think that on the days like this, hopefully I will play more and more forehands, it's a good weapon. I think I can do many things with that forehand. I can play flat and I can play with a spin and I can also attack," Tsurenko said, after beating world No. 2 Caroline Wozniacki in the second round.
"This is actually my favorite shot now. I would be happy to use it more as I can and to play aggressive with it."
Her forehand is just the latest in a long line of improvements for the Ukrainian as she's logged years of service on tour.
This season, she's reached the second week of two Slams, and won her fourth career WTA title.
She scored her first-ever win over a Top 5 player when she defeated Wozniacki here.
She entered this tournament ranked world No. 36, and is guaranteed to set a new career-high after the event. She is the lone unseeded player among the last eight women.
"I feel that I play more confident, I play more calm, and I feel that I have a good spirit now," she said, reflecting on one of her best seasons, to date. "I'm ready to fight. I'm ready for any kind of challenge on court."
This fornight, she's proven that age is just a number. All five of Tsurenko's opponents at the US Open have been younger than she is, including two by nearly a decade: the 19-year-old Vondrousova, and her next opponent, 20-year-old Naomi Osaka, the No. 20 seed.
"We played once, but many years ago, I think in some small tournament in Mexico, and she beat me. I was impressed with her serve and forehand. Nothing's really changed in her game. She's just more consistent and even more powerful now," the Ukrainian said, assessing Osaka.
"I think she likes to play on hard courts. She likes to attack all the time. I'm playing a little different style of tennis, so we'll see."
