NEW YORK • After Jack Sock completed his third-round upset of Marin Cilic in straight sets on Friday in the Louis Armstrong Stadium, he turned to the crowd and, with a big smile, showed a few fencing moves on the court.
The gesture was a nod to Sock's friend Miles Chamley-Watson, a fencer who, like Sock, competed in the Olympic Games last month in Rio de Janeiro.
Chamley-Watson had come to support fellow American Sock in his match against the No. 7 seed Cilic.
"Kind of on the spot, I thought of turning the racket into - I think it's called a foil? Is that what they call it?" Sock said afterwards.
"I thought of turning the racket into one of those and doing something for him for coming out (to watch me).
"I think people were enjoying it. I've seen the video. It looks pretty funny, actually."
It was an amusing moment at the end of a clinical performance. Sock, the No. 26 seed, rolled to a 6-4, 6-3, 6-3 victory in a match that was even less competitive than the score would indicate.
Sock never faced a break point and needed only 101 minutes to dispatch the Croatian - who won the Open two years ago - to reach the fourth round for only the second time in 16 Grand Slam appearances, and for the first time in seven trips to Flushing Meadows.
Sock, 23, won a pair of medals in Rio - gold in the mixed doubles and bronze in the men's doubles - and reached the third round at the French Open and Wimbledon earlier this season.
Now, he is one win away from his first Grand Slam quarter-final. He will meet No. 9 seed Jo-Wilfried Tsonga in the fourth round today.
But Sock made it clear he is far from satisfied.
"I feel like I'm definitely more on a mission this year," he said.
"Going forward, my goal is to be competing to win tournaments that I'm playing in instead of just being content with making the quarters of whatever tournament it is."
While Sock had an unexpectedly easy time, compatriot and eighth seed Madison Keys was involved in a thrilling fightback when she rallied from 1-5 down in the final set to reel off five straight games, defeating Japan's Naomi Osaka 7-5, 4-6, 7-6 (7-3).
The 18-year-old Osaka was reduced to tears as she twice served for the match but choked under the immense pressure.
"Obviously those aren't the most fun matches," Keys said.
"But I just knew that if I stayed in the match I could maybe have a chance to come back, and get back into it.
"No matter what the score was, once I was able to get a little bit of momentum, I felt like I found my game a bit more. At that point, I knew I had to kind of step up, or else I was going to be going home.
"This is the greatest comeback of my career, hands down."
Keys who will face two-time runner-up Caroline Wozniacki for a quarter-final spot today.
WASHINGTON POST, AGENCE FRANCE-PRESSE
US OPEN DAY 7
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