In an interview to ESPN, the seven-time Grand Slam winner John McEnroe praised Roger Federer's, Rafael Nadal's and Novak Djokovic's ability to improve. The American former player said: "Of the top three guys, Nadal's improved the most.
For a guy who was thought of as a clay-court player, who didn't serve particularly big, who didn't come to net much, that he's been able to adapt his game and add to it in order to become an incredible all-court player.
He's shortened points. Him and his team have realized that he could actually have more longevity, that he didn't have to be as passive and wait -- he could play more aggressively. He's found the perfect mix between offense and defense.
He's done things that have just shocked players where he's stood on the court returning. He's as far back as you can possibly get. He's bought himself some extra time and gotten in the heads of a lot of players."
McEnroe's brother Patrick added: "I was watching the French Open final this year and I was just amazed. Obviously we've always known that Nadal stands way back and he hits with this crazy topspin, but the way he's started to take the ball earlier.
And when he had Dominic Thiem pulled wide, he would anticipate the next one was coming cross-court and he'd already be moving forward. His tennis IQ, if it's even possible, has improved. He's had to force himself to do that to get better on grass and on hard courts, and that has just made him an all-round better player.
Not only is he this incredible physical specimen, but his pure tennis ability has improved over the years, too. You look at Roger, and the way he's been able to take care of himself physically and still move the way he can move -- he's almost 38 -- is just amazing."