Jack Sock moved up to a career-high No. 60 in this week's ATP Tour rankings.
Sock, 21, has climbed 16 spots over the last three weeks thanks to semifinal appearances at the Hall of Fame Tennis Championships and Atlanta Open. The Lincoln, Neb., native is now the No. 2 American, behind John Isner, who defeated Sock in the Atlanta semifinals on Saturday. Isner went on to defend his title and remain at No. 12.
Sock also partnered with Canada's Vasek Pospisil to win the doubles title in Atlanta, making them 2-for-2 as a team after upsetting Bob and Mike Bryan in the Wimbledon final earlier this month. Sock and Pospisil are up to No. 7 in the race for eight qualifying slots at the ATP World Tour Finals in November in London.
In other singles rankings news:
• Croatia Open semifinalist Marin Cilic rose to No. 18 from No. 22, his highest position since returning from a four-month doping ban last October.
• Pablo Cuevas of Uruguay went from 60th to a career-high 40th after winning the Croatia Open as a qualifier for his second title in his last two tournaments. The 28-year-old was ranked No. 111 before a two-title run that included victories over top-30 players Fabio Fognini, Tommy Robredo and Fernando Verdasco.
• New No. 44 Pablo Andujar of Spain had the biggest jump in the top 100, surging 27 spots after winning the Swiss Open.