Juan Martin del Potro spends more time watching tennis than he does playing tennis these days.
The 2009 US Open champion has removed the splint from his surgically-repaired left wrist. Twice a day, he does strength and flexibility exercises.
Video: Federer's Poetic Smash Shank
In a post detailing his ongoing physical therapy, del Potro reveals he started one recent rehab session listening to the Red Hot Chili Peppers' song "Scar Tissue", an appropriate anthem for a man whose career has been sidetracked by multiple wrist surgeries.
"I can lift some stuff with the left hand but I must not rush," del Potro wrote. "This is the beginning of a long process. Step by step. Patience and perseverance. I’ve got a degree on that."
The former world No. 4 has delivered some memorable matches against the game's top players.
In celebration of del Potro's 27th birthday today, here are a few of our favorite highlights from the man who made history as the first player to beat Rafael Nadal and Roger Federer at the same Grand Slam tournament in capturing the 2009 US Open.
Del Potro dethrones Federer in 2009 US Open final
In a stirring, four hour, six-minute final played on a Monday afternoon, del Potro snapped Federer's 40-match U.S. Open winning streak in scoring the biggest Flushing Meadows upset since a 20-year-old Marat Safin stunningly swept Pete Sampras in the 2000 final.
Two points from defeat, the 6-foot-6 Argentine dug in and seemed to grow in confidence with each passing game in the final set. Del Potro was so overwhelming at times he was content to spin in his serve and blast away with his flat shots that forced Federer into stretched, defensive positions.
"I don't have words to explain it," del Potro told the crowd. "I have two dreams: one is (to win) the US Open and the other one is to be like Roger. One is done but I need to improve a lot to be like (Federer)."
Del Potro defeats Rafael Nadal in the 2013 Shanghai Rolex Masters Semifinals
Del Potro defeats Novak Djokovic in the 2012 Olympic bronze-medal match.
Djokovic defeats del Potro in the 2013 Wimbledon Semifinals
Del Potro defeats Roger Federer in the 2013 Basel Final
Del Potro defeats Bernard Tomic in the 2014 Sydney Final for his last title