SportsJuan Martin Del Potro returns to US Open 4th round, beating Leonardo MayerNasir QureshiSeptember 3, 2012September 3, 2012 by Nasir QureshiSeptember 3, 2012September 3, 2012 New York: Juan Martin del Potro beat countryman Leonardo Mayer 6-3, 7-5, 7-6 to return to the fourth round of the US Open for the...