ATLANTA (AP) Jack Sock beat Alejandro Gonzalez 6-2, 6-4 in the first round of the BB&T Atlanta Open on Tuesday.
Sock and partner Vasek Popisil won the doubles title at Wimbledon earlier this month, upsetting the top-ranked team of Mike and Bob Bryan in the finals.
The 21-year-old Sock said doubles success on the greatest stage in tennis has boosted his singles game.
''(It's) just belief in your game, belief in 30-all points, deuce points, break-point down or break-point up . . . you sort of have that confidence that you've done it,'' Sock said. ''At Wimbledon, Vasek and I were in a lot of tough positions. We were able to pull through them and get out of there, and you have that in the back of your mind, and that sense of confidence that you can battle through a lot of things.''
Sock finished off Gonzalez in 1 hour, 6 minutes by winning 89 percent of his quality first serves, and relying on his forehand to break Gonzalez's serve twice in the first set and once in the second.
Eight of the first nine first-round matches lasted two sets Tuesday.
In the only three-set match, Robby Ginepri beat Sergiy Stakhovsky of Ukraine 7-6, 3-6, 6-0.
Ranked as high as No. 15 in 2005 and in the top 100 for most of the next several years, Ginepri entered Atlanta 0-4 this year in ATP and Grand Slam matches, and a modest 5-3 in Challenger events.
Tuesday, he fought off eight of 11 break points, and Stakhovsky double-faulted 11 times.
American men went 3-3 Tuesday. In addition to Sock and Ginepri, Tim Smyczek was a winner with a 6-0, 6-2 rout of fellow American Ryan Harrison.
Also, Russian Denis Istomin, the No. 6 seed, beat Rajeev Ram 6-1, 6-4, and Slovakia's Lukas Lacko beat Nathan Pasha 6-2, 7-5.
Ram and Pasha made the main draw as qualifiers.
In doubles action, Sock and Popisil broke the Colombian pair of Gonzalez and Juan-Carlos Spir once in each set on the way to a tough 6-4, 6-4 win.