U.S. tennis star Jack Sock takes CNN’s ‘Sock Challenge’!!
The American won his first ATP Masters title in Paris on Sunday to break into the world's top 10 and qualify for the World Tour Finals at London's O2.Follow @cnnsportBut could he keep that remarkable winning streak going in CNN Sport's specially designed tennis history challenge? We asked Jack to identify 10 tennis players — past and present — just by looking at their socks. Watch the video above if you want to the know the answer to the burning question … just how well does Jack Sock know his socks?The 25-year-old Sock, who was born in Lincoln, Nebraska, is already an established doubles player having won two majors, two Masters tournaments and even Olympic gold and bronze medals at the 2016 Games in Rio. But he's now starting to make waves in the singles game as well. A number of big names were missing in Paris but Sock still had to show plenty of psychological strength to get his hands on the trophy, surviving two match points in his first-round match and fighting from a set down in the final to beat Serbia's Filip Krajinovic."Tennis is a very physical sport but the mental side is big too," Sock told CNN Sport's Alex Thomas after flying into London from Paris."I spent the last 12 to 18 months really honing in on it. The first match in Paris where I was down big in the third set, to be able to come back from that, maybe I wouldn't have been able to do that a couple of years ago."Sock is the first American to win a Masters title winner since Andy Roddick at the 2010 Miami Open and he'll finish the year at the number one U.S. player for the first time in his career ahead of Sam Querrey and John Isner. He's also the first player from the States to compete at the World Tour Finals since Mardy Fish in 2011 — he just wishes he had more company. "I'm happy to be part of it," said Sock who told CNN back in January that he believes he's capable of winning majors. "But I hope one day that there's a group of Americans that are here playing in the year-end finals." Sock is now ranked No.9 in the world — his first time in the top 10 — and was congratulated on social media by some of the greats of the game including Boris Becker and Rod Laver. However, there has been one downside to Sock's recent success.His qualification for London meant he had to cancel a round of golf with Isner at one of the best courses in the world, Augusta National, the prestigious home of The Masters where it is almost impossible to get a tee-time.Head to CNN.com/sport for more stories & featuresAugusta would've been nice but Sock is no doubt relishing the chance to compete against the tennis elite — including the likes of Roger Federer and Rafa Nadal — at one of the biggest events of the year outside of the majors at London's O2.And if his tennis is half as good as his performance in the CNN Sock challenge, watch out Roger and Rafa.