Defending champion Rafael Nadal, made an emotional statement after being forced to withdraw from his US Open semi-final against Juan Martin del Potro yesterday.

Having also had to wear tape on his knee, in his third round match against Karen Khachanov, and trailing by two sets here, Rafa was in too much pain to continue and had no choice but to surrender his crown prematurely.

Plagued by injury throughout his otherwise glittering career, this was the second time that he has to withdraw from a Grand Slam due to injury and he started to struggle in the first set against Del Potro.

Afterwards, Rafa addressed the press and admitted to having struggled with the injury throughout the tournament.

"I had some issues during the tournament," he said, per The Metro. "As everybody knows, I had an issue, it was in the second or third match. Then I think was little bit better.

"But, yeah, I think was 2-All in the first, 15-Love, something like this in the first set, that I felt. I said too my box immediately that I felt something on the knee.

"After that, I was just trying to see if in some moment the thing can improve during the match. But no, was not the day.

“I waited as much as I can. You could imagine very difficult for me to say good-bye before the match finish. But at some point you have to take a decision. It was so difficult for me to keep playing at the same time that way, having too much pain."

He claimed that the match had become one-way traffic at the point that he was forced to concede defeat.

“That was not a tennis match at the end, no? It was just one player playing, the other one staying on the other side of the court. I hate to retire, but stay one more set out there playing like this will be too much for me."

Del Potro will now face the winner of the other semi-final, Novak Djokovic, in Sunday’s final and Nadal was able to put aside his disappointment and wish his conquerer, who has had struggles of his own, the best for the rest of the tournament.

"I can’t say that I am happy because I am not. I will not lie you.

"But, yes, he’s a player that went through lot of issues during his career, like me too. I know how tough is this thing. I know how much frustration can be when you can’t do the thing that you want to do. He knows very well.

"Happy to him that he’s able to be back in his top level. Yeah, wish him all the best. For him will be huge if he’s able to win again a Grand Slam."

As Del Potro concentrates on his opportunity to win a second Grand Slam, the outgoing champion will instead have to ponder his future and wonder what might have been, were it not for yet more injury woe.