Four-times NBA Most Valuable Player

"Without Muhammad Ali, I wouldn't be sitting up here talking to you guys, I wouldn't be able to walk in restaurants, wouldn't be able to go anywhere where blacks weren't allowed back in those days," James said.

"We knew what a great boxer he was but that was only 20 percent (of what) made him as great as he was. He ended up in jail because of his beliefs.

"That was a guy who stood up for so many different things at a time when it was difficult for African-Americans to even walk the streets."

James added that Ali sacrificed so much in his life knowing it would benefit the next generation.

"I give all credit to (Ali), because he was the first icon, the greatest of all-time and it had zero to do with his accomplishments inside the ring.

"I've spoken up on a lot of issues that other athletes might not speak upon, but feel it's my duty to carry on the legacy of the guys who did it before me."

Jerry West, who was a champion NBA player with the Los Angeles Lakers in the same era as Ali, spoke about what it was like to be in Ali's presence.

READ: Sporting superstars pay tribute to Ali

"You almost felt a God-like presence around him," said West, 78, who is now a board member with the Warriors.

"He had IT. He had IT. Certain people are courageous in doing what no other athlete probably would have dared to have done, particularly a black athlete.