Thirteen Grand Slams for a guy who is 27 years old is incredible," said Djokovic, a six-time major winner. "Whatever he achieved so far in his career is something that everybody should respect, no question about it. He's definitely one of the best tennis players ever to play the game."
Sign Up for our Newsletter
Don't get stuck on the sidelines! Sign up to get exclusives, daily highlights, analysis and more—delivered right to your inbox!