That’s the opinion of pundit Greg Rusedski.
The Spaniard overcame a huge scare to see off Russian Khachanov 5-7, 7-5, 7-6 (9-7), 7-6 (7-3) at Arthur Ashe Stadium to move into the fourth round and face Nikoloz Basilashvili.
But after dropping the first set Nadal had to have his right knee taped up, causing concerns that he may be carrying a fitness issue.
The world No 1 produced a stunning response to Khachanov’s pressure after seizing the second set, showing typical determination and desire to come out on top in an enthralling four-hour, 23-minute match at Flushing Meadows.
And Rusedski is confident that Nadal’s hopes of retaining his title in New York will not be hampered by injury.
Rusedski said on Amazon Prime’s live coverage: “He says it didn’t bother him.
“He knows how to manage it and he knows what he has to do.
“And the good news is he didn’t take any painkillers on the court. When a player takes painkillers, then you know something is usually more serious.”
Speaking to the press afterwards, Nadal insisted he will be fully fit to face Georgia’s Basilashvili next time out although he hinted that he is carrying a problem.
“[It was] Just something that I felt, but I try always during the tournaments to not speak much about these kind of things,” he revealed.
“When the tournament is over it is better and easier to talk.
“But my personal feeling is I’m going to be at my 100% for the next one.”
Nadal’s trainer Carlos Moya also spoke on the issue but was keen to play it down, praising the 17-time Grand Slam champion for how he never needs minor niggles to become a problem on court.
As quoted by journalist Carole Bouchard, Moya said: “Rafa’s knee felt sore but [it is] nothing to worry about.
“Sometimes he feels it more than other but he deals with it really well so that’s not an excuse.”
Nadal faces four more best-of-five set matches in order to keep his title as US Open champion and acknowledged the drain of his lengthy clash with Khachanov.
“For me personally, of course, it was a physical, demanding match. It was a mentally demanding match,” he added.
“That’s why we practice every day, to play these kind of matches in a great atmosphere in front of an amazing crowd.
“Very happy to be through. Very happy to have the chance to play again.”