Dan Kitwood/Getty Images
Mitchell Krueger posted some of the most successful results of any American junior at Grand Slam tournaments in 2012, reaching the Roland Garros and Wimbledon boys' singles semifinals and the doubles quarterfinals at the US Open with partner Mackenzie McDonald. Among his other results during the year, the 18-year-old Texas native won the boys' 18s title at the International Spring Championship and captured the doubles title with Alexios Halebian at the Easter Bowl.