Kazuhiro Nogi/Getty Images
Coco Vandeweghe had a breakthrough year in 2010, winning back-to-back singles titles at $50,000 Carson in May and $25,000 El Paso in June, as well as the doubles championship at $75,000 Phoenix in November. On the WTA Tour, the 19-year-old defeated Wimbledon and US Open runner-up Vera Zvonareva en route to the quarterfinals at the Olympus US Open Series event in San Diego and, this fall, knocked out five top-100 players to qualify and advance to the quarterfinals of the $2 million event in Tokyo. Vandeweghe, who also competed for the U.S. team that faced Italy in the 2010 Fed Cup final, finished the year ranked No. 116 in the world, up an impressive 238 spots from her year-end ranking of No. 354 at the end of 2009.