Breaking Down What Rafael Nadal Must Do to Beat Philipp Kohlschreiber in Round 4

Through three rounds at the 2013 U.S. Open, No. 2 seed Rafael Nadal has been nearly untouchable.  The 12-time Grand Slam champion has picked up straight-set victories over Ryan Harrison, Rogerio Dutra Silva and Ivan Dodig so far at Flushing Meadows, but will face his toughest test of the tournament so far on Monday night in the form of No. 22-seeded Philipp Kohlschreiber.  As noted by tennis journalist Ricky Dimon, the two men have seen their fair share of each other over the past decade: Kohl...