What impact the Laver Cup has on the future of Davis Cup, the long-standing competition between nations, is still debatable. But there is a proposal from the International Tennis Federation to play the top level of Davis Cup in a single-week, 18-nation format. It must be approved by a vote of the membership.
"It just takes so much out of the players to be available four weekends during the year every single year," Federer said. "I played a lot of Davis Cup when I was younger and happy I did. I was happy it existed, but eventually it was just too much."
Federer added: "I do believe that the Laver Cup has sparked some change, some inspiration to other cups that maybe we'll see in tennis. But that's a good thing. We'll take that as a sign of flattery."
McEnroe, once a staple for the U.S. Davis Cup team, said changes in that competition are overdue and certainly the success of the Laver Cup has not gone unnoticed.
"For me, I say, 'When's the last time anyone's asked me about how many Davis Cup teams I was part of winning?'" McEnroe said.
"In the last 10 years, how many people have asked me that? You know how many people? None. Which is sad, 'cause I played a lot of Davis Cup and I loved it."
The 2018 Laver Cup will be played Sept. 21-23 at United Center before returning to Europe the following year.