The 24th seed swept Roger Federer aside in four sets in the quarter-finals on Wednesday after coming from the brink to beat Austrian sixth seed Dominic Thiem in the previous round, his big serve and mighty forehand proving too hot for his rivals to handle.
World number one Nadal, however, is left-handed and that means the Spaniard will find it easier to avoid Del Potro’s forehand -- possibly the best on tour.
“He’s a lefty guy, so he has chance to find easily my backhand. So I don’t know what’s gonna be my strategy for that match,” said Del Potro, whose career has been hampered by injuries and surgeries.
“But for sure I will try to make winners with my forehands and don’t run too much, because my legs are tired.”
Del Potro, however, has sweet memories against Nadal, having beaten him 6-2 6-2 6-2 in the final in Flushing Meadows in 2009.
Although he has a 5-8 win-loss record against the Spanish juggernaut, he has won their last two matches, at the Rio Olympics last year and at the Shanghai Masters in 2013.
But Nadal is an all different player, having won his 10th French Open title this year. In New York, he has been barely troubled to advance into the last four, crushing Russian teenager Andrey Rublev in the quarter-finals.
“It is gonna be a different match than in the past,” said Del Potro.
“He’s the No. 1 player of the world, and he’s playing so confident this tournament.”
And Del Potro, who was on the brink of retirement in the fourth round after falling ill, believes he is not in the best possible shape.
“Physically I‘m not in the perfect conditions, but when you play semi-finals on the Grand Slam, everything can happen,” he said.
“So you must be ready for the chance and playing against Rafa in my favourite tournament, I will try to enjoy the atmosphere, the game, and I know if I play my best tennis, I could be a danger for him.”