Alexander Zverev says defending his ATP Washington Open title on Sunday shows growing in strength and maturity, but the World No. 3 still sees a big gap to Rafael Nadal and Roger Federer. The German, 21, won his third title of the year and the ninth of his career by defeating Australian teen Alex De Minaur 6-2, 6-4 in the 50th edition of the US Open tune-up event.

"What a fantastic week for me," Zverev said. "Winning a tournament on its 50th anniversary is something amazing. This has been a very special week for me. [Defending a title] feels great and shows mental strength as well. It shows a little maturity, I think." While Zverev stands atop a generation of rising young stars, he still puts 20-time Grand Slam-winner Federer, 36, and 17-time Grand Slam champion Nadal, 32, on the highest of pedestals.