AGE: 20
OCCUPATION: Professional tennis player
NUMBER OF TIME COVERS: 0
PREVIOUS APPEARANCES ON THE TIME 100: 0
PRO: The Serbian denied the seemingly unbeatable Roger Federer the 2008 Australian Open title, and in the process, became the youngest player in the Open era to have reached all four Grand Slam semi-finals.
CON: He has one Grand Slam. Federer has 12.