MIAMI -- By most accounts, undefeated boxing champion Floyd Mayweather Jr. delivered a knockout message Sunday to the Miami Heat as they set out to become just the fourth team in NBA history to win three straight titles.
Mayweather was seen exiting the Heat's practice facility just as reporters were entering to interview players. By then, he had already gotten a power message across to an awed LeBron James and several of his teammates.
"With him being 17 years-and-0 -- we're trying to defend two titles -- he's been defending for a long time," James said. "He definitely knows where we're coming from. It's definitely exciting to have someone, one of the greatest of all time, to be in your presence. It's something you can talk about years from now when you look back on the history of sports. That guy was at our practice."
Heat players said Mayweather, who is 45-0 and has won titles in five different weight divisions, talked to the team about remaining on top in the face of what is expected to be stiffer competition from much-improved contenders across the league.
Miami spent Sunday preparing for its preseason opener Monday against Atlanta, and the two-time defending champions open the regular season Oct. 29 against Chicago. The Heat are trying to become just the fourth team in NBA history to win three consecutive titles.
Mayweather, 36, has collected at least eight major championship belts over his decorated career. He has attended several Heat games over the past three seasons and has fought at least once at AmericanAirlines arena during a 17-year boxing career that has made him one of the wealthiest prizefighters in history.
But it's rare moment when Heat team president Pat Riley, known for running a tight-knit organization, has allowed outsiders -- even high-profile celebrities -- to attend workouts and address the team.
Riley, however, is also a huge boxing fan and has followed the sport since before his playing days in the NBA. Heat star Dwyane Wade, who has been in Miami for all 11 of his NBA seasons, said he didn't recall a similar practice visit from another icon.
"From one champion to another, he just talked about being proud of us and how we handled ourselves," Wade said. "He knows, as a champion, how hard it is to go out there and compete when people try to take you down, take what you work for. He kept telling us how proud he is of us. If you got up today and you were a little tired, you walk in and see the champ, you work a little harder."
Mayweather certainly has been a polarizing figure among the Heat. James, Wade and several other players on the team are huge fans of his flamboyant, brash style in and out of the ring. Mayweather is known to flash his riches and has posted photos on social media of betting slips when he's won money gambling on sports, including Heat games.
But Heat coach Erik Spoelstra has been a loyal fan of boxing legend Manny Pacquiao, who was long regarded as Mayweather's biggest rival though the two have never met in the ring despite years of failed negotiations to fight.
Spoelstra, who is of Filipino descent like Pacquiao, played coy when asked about Mayweather's presence Sunday and deferred questions about his message to other Heat players. Spoelstra did say the Mayweather deserved universal respect as a world champion who has remained at the top of his sport for the better part of two decades.
"I thought about messing with [Spoelstra] just a little bit," Heat center Chris Bosh said. "We always try to give Spo a tough time when anybody from the Philippines goes down. That's no disrespect to Pacquiao. He's one of the greatest to ever do it. But we had the undefeated champ here. It was fantastic just to be full of that energy and be in that aura and just soak up whatever he had to say."