US Open hangover drags on for Del Potro?

Question

Juan Martin del Potro did what was almost the unthinkable at the 2009 US Open – and that was to beat Roger Federer in the final at Flushing Meadows. But in the months that have followed, the results haven’t quite stacked up for the Argentinian and his fourth round exit (defeated by Marin Cilic) from the Australian Open is another case of del Potro performing below expectations. Tellingly, Cilic thumped 67 winners to del Potro’s 46 for the match and won a staggering 41 points at the net to his opponent’s 13 to take the match.