 Complete the following phrase:  Del Potro has a record against Rafael Nadal. Del Potro bested Nadal in the semifinals en route to his 2009 US Open title which was the first time a player managed to beat both Roger Federer and Nadal in the same Grand Slam tournament Novak Djokovic did this at the US Open 2011. However the Spaniard managed to win both times in the Indian Wells Masters encounters, in the 2011 semifinal and the 2013 final. Nadal also won the fourth and last rubber of the 2011 Davis Cup final against the Argentine. Del Potro gained the upper hand at the 2013 Shanghai Masters, defeating Nadal to reach the final where he lost to Djokovic. Del Potro defeated Nadal in a third set tiebreak in the semifinal of the 