Muhammad Ali paid a heartfelt tribute and cricketers and golfers donned black armbands and ribbons on Friday as the sports world united in respect and mourning after the death of Nelson Mandela.
Heavyweight boxing legend Ali said Mandela "taught us forgiveness on a grand scale" as athletes and officials from Australia to Brazil and at home in South Africa expressed their sadness.
Fifa chief Sepp Blatter called Mandela "one of the greatest humanists of our time" and Tiger Woods said he had been inspired by South Africa's anti-apartheid hero.
In Sun City north of Johannesburg, golfer Ernie Els hailed the former South African president as an "iconic leader".
"You cannot say anything bad about the man. He fought for what he believed in, went to prison for so many years and came out to lead our country up until now," said the South African champion, who wore a black ribbon when he went out to play in the Nedbank Golf Challenge.
"He was the father of our country and our continent. It's just very sad that he had to go. He was 95 and led a full life but a lot of that wasn't spent on what he was so good at because he was away for so many years."
Australia and England's cricketers held a minute's silence before play in the second Ashes Test in Adelaide, and later donned black armbands.
Ali, in a statement from the Ali Center in Louisville, Kentucky, paid tribute to South Africa's first democratically elected president, who led the country peacefully out of apartheid rule after spending nearly three decades in prison.
"He made us realise, we are our brother's keeper and that our brothers come in all colours," said Ali, a towering figure in America's civil rights movement.
"What I will remember most about Mr Mandela is that he was a man whose heart, soul and spirit could not be contained or restrained by racial and economic injustices, metal bars or the burden of hate and revenge."
Brazilian football legend Pele said on Twitter that Mandela was "one of the most influential people in my life".
"He was my hero, my friend, and also a companion to me in our fight for the people and for world peace," he added.
International Olympic Committee president Thomas Bach called Mandela "a great friend and a hero of humanity".
"His attitude towards sport can make us proud - proud at his understanding of the potential of sport to bring inclusion," Bach said.
Blatter, who is attending the 2014 World Cup draw in Brazil, said he and Mandela had "shared an unwavering belief in the extraordinary power of football (and sport generally) to unite people in peace and friendship".
New Zealand's rugby board hailed Mandela's "far-reaching" influence on sport after he inspired South Africa to victory over the All Blacks in the 1995 World Cup final.
Mandela famously appeared at the final in Johannesburg wearing a Springboks jersey - a stark symbol of white South Africa - in an act that electrified the stadium.
"We have lost a champion for our game, a leader whose inspiration ensured the Rugby World Cup in 1995 was a remarkable time for our sport and whose influence on sport has been far-reaching," said New Zealand Rugby Union chief executive Steve Tew.
International Rugby Board chairman Bernard Lapasset said: "I was honoured to be with him during the historic days of 1995 Rugby World Cup and saw his incredible impact on his nation and his people. His wisdom, intelligence and sheer presence was a wonder to behold."
Woods, the world's number one golfer, recalled having lunch with Mandela in 1998, the year after his first Masters triumph.
"It was one of the most inspiring times I've ever had in my life," said Woods. "I don't think any of us probably here could have survived that and come out as humble and as dignified as he did."
South African golf great Gary Player called Mandela "our beloved Father of the South African nation".
Football superstars Cristiano Ronaldo and David Beckham sent tributes, while Formula One driver Lewis Hamilton posted a picture of himself with Mandela on his Facebook page.
Former heavyweight champion Mike Tyson called Mandela a "great man" and a "true fan" of boxing, which was a sport he pursued as a young man.
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