CHICAGO (AP) -- The Laver Cup was a hit last year, and now Roger Federer is hoping it proves popular on U.S. soil.
The 20-time Grand Slam champion made his first-ever visit to Chicago on Monday to promote the second Laver Cup, a team competition that debuted last year in Prague.
Federer, shaking off a three-set loss to Juan Martin del Potro on Sunday in the final at Indian Wells that ended his 17-match winning streak, was joined by tennis legends Rod Laver and John McEnroe, along with young Australian star Nick Kyrgios.
Federer's management team was instrumental in launching the Laver Cup, which pits Team Europe against Team World. After its third year, he said he'll entertain possible changes to the format.
''Down the road I'm totally open to anything,'' Federer said. ''I've heard already from women players. They would love to do it as well.''
Four of the six players on each team are chosen on rankings after Wimbledon. The other two are captain's picks, and captain McEnroe didn't wait Monday - he announced the talented Kyrgios was already on the World Team.
Kyrgios lost a tight final singles match to Federer in Prague last season, which clinched the cup for Team Europe.
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.