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Rising star Jack Sock's impressive results in 2012 include capturing the singles title at the $100,000 Tiburon, Calif., Challenger, reaching the singles final at the Champaign, Ill., Challenger, and reaching doubles finals at Challengers in Honolulu, Dallas and Charlottesville, Va. Among his other results this year, the 20-year-old Nebraska native reached the quarterfinals at the ATP event in Atlanta as well as the third round of the US Open, where he lost a close four-set match to No. 11 seed Nicolas Almagro, 7-6 (3), 6-7 (4), 7-6 (2), 6-1. Sock ended 2012 ranked 150th in the world, up 282 spots from his 2011 year-end ranking of No. 382.