Canadian and Wimbledon runner-up Eugenie Bouchard pulled out a suddenly tight match Saturday night, edging 30th-seeded Barbora Zahlavova Strycova of the Czech Republic 6-2, 6-7 (2), 6-4 to reach the U.S. Open's fourth round for the first time.
The seventh-seeded Bouchard was the only woman to make it to at least the semifinals at each of the year's first three Grand Slam tournaments.
At Wimbledon, she became the first Canadian to appear in a major singles final.
To get to the quarterfinals at Flushing Meadows, Bouchard will need to beat No. 17 Ekaterina Makarova.
Zahlavova Strycova fell to 1-28 in matches against opponents ranked in the top 10.
After breaking to get to 4-all in Saturday's third set, Zahlavova Strycova double-faulted to fall behind 5-4. Bouchard then served out the victory.
Bouchard dazzled for a second straight match under the Arthur Ashe showcase court lights, overcoming a run of poor play but defeating Barbora Zahlavova Strycova 6-2, 6-7 (2), 6-4 in just over two and a half hours.
Bouchard remains impressed by the massive 24,000 capacity stadium, the largest in the sport, where she has played her last two matches.
"I felt great," said the seventh seed, who will face Ekaterina Makarova of Russia in the fourth round. "With all the energy around, I felt we had to put on a show.
"I don't know if I can ever get used to something so special as here. It was windy and difficult tonight but I don't care, I'd play here any time."
Bouchard fought hard
The 20-year-old, from Westmount, Que., fought from a break down in the second set but lost the set in a tiebreaker.
"I was disappointed in myself, not necessarily about going to a third, but by my level in the second set," she said. "I was surprised I could do so many unforced errors in one set.
"That's something I definitely don't want to repeat again. But I'm determined to do better in my next match."
The third set was full of plot twists as Bouchard finally ended a run of three straight breaks of serve between the two as her Czech opponent double-faulted for the eighth time to drop serve in the ninth game.
Leading 5-4, Bouchard served out the victory to continue the Grand Slam run of form which has taken her into the WTA top 10.
"In in the third set, when things still weren't going my way, I felt a little lull in my game," Bouchard said. "In the second set I felt it, and in the beginning of the third.
"Somehow I was able to snap out of it and turn it around. It's important to at least realize when I'm in those moments, try to get myself out of it, which I was able to do."
The win over Zahlavova Strycova, the 30th seed, marked Bouchard's third victory over the veteran. Bouchard also won their meetings in Osaka last autumn and in Nurnberg on clay this spring.
In doubles action, Vancouver's Vasek Pospisil and his American partner Jack Sock advanced to the third round with a 6-4, 6-2 win over Marin Draganja and Florin Mergea.