Novak Djokovic became the world's third-ranked tennis player on July 9, 2007. For the better part of the next four years he was the sport's top doormat. First Roger Federer and then Rafa Nadal would regularly wipe their feet on him en route to major titles; nine times they stomped him in Grand Slam events.
Djokovic's renowned sense of humor — he's a great mimic of his fellow pros — must have helped him. But while he yukked it up, he also upped his training regimen and refined his exquisite baseline shotmaking. No one has a more lethal backhand down the line. He got mentally tougher too. Last year Djokovic reached No. 1 in dominating fashion, winning at the Australian Open, Wimbledon and the U.S. Open and dispatching both nemeses. He started 2012 by beating Nadal in a five-set, nearly six-hour epic for the Australian title. "It's the result of the really hard work that I put into it," says Djokovic, 24, now a national hero in his native Serbia.
Djokovic's tennis hero is Pete Sampras, a serve-and-volley maestro who spent a record 286 weeks as top gun. Djokovic recognizes that the game today is different — more baseline power and speed, less touch. And with Nadal and Federer hounding him, staying No. 1 will be difficult. But having worked for years to get there, he'll enjoy every moment of it.
Saporito is TIME's sports editor