At the British Open, Tiger Woods talked about the unique energy Mandela exuded when they first met, while some of South Africa's biggest stars proudly tweeted pictures of their own encounters with the adored former president.
FIFA President Sepp Blatter wrote to Mandela to wish him a happy birthday and thank him for "championing" the 2010 World Cup in South Africa, and Premier League club Manchester City will play a game later Thursday in his honour.
"Today we remember your courageous fight against oppression and the inspirational example you set to others who are battling injustice," Blatter wrote to South Africa's first democratic president. "May this message transmit to you all the energy, strength and goodwill of the football community as you continue your recovery from illness."
The aging Mandela remains hospitalized but his birthday coincided with a statement from South Africa's current president, Jacob Zuma, saying his health was improving.
Mandela's unifying legacy pervades nearly all sports, a strong connection that meant a question about the Nobel Peace Prize winner in the buildup to a major golf tournament wasn't at all out of place this week.
Woods, at the British Open in Scotland, said his 1998 meeting with Mandela was an experience he would "never, ever forget" and recounted the visit with his late father to the then-president's Johannesburg home.
"It still gives me chills to this day, thinking about it," Woods said this week. "A gentleman asked us to go into this side room ... and we walked in the room and my dad and I were just kind of looking around. And I said, 'Dad, do you feel that?' And he says, 'Yeah, it feels different in this room.' And it was just like a different energy in the room.
"We just looked at each other and just shrugged our shoulders. And maybe, I'm guessing probably 30 seconds later, I heard some movement behind me and it was President Mandela folding up the paper. And it was pretty amazing. The energy that he has, that he exudes, is unlike any person I've ever met."
In South Africa, Mandela's inspirational appearances at the Rugby World Cup final in 1995 and football's African Cup of Nations final a year later are as much a part of the country's sporting heritage as its winning teams on those days — maybe more.
His advanced years and numerous visits to the hospital recently have left South Africans fearing for their ailing father figure, but sportsmen and sportswomen took the opportunity to celebrate his birthday.
A list of stars paid tribute, some affectionately referring to Mandela by his clan name Madiba, others using "Tata," a word that means father.
"Happy birthday #Madiba," Bryan Habana, one of South Africa's top rugby players and a 2007 World Cup winner, wrote on Twitter. "As a nation we salute you and keep you in our prayers!"
Habana also posted a photograph of himself and teammates with a smiling Mandela on a previous birthday.
South Africa cricket captain AB de Villiers, in Sri Lanka for a series, said: "There are no words to describe the impact Madiba has made on us as cricketers and for sport in our country."
Olympic swimming champions Chad le Clos, Cameron van der Burgh and Kirsty Coventry, who is from Zimbabwe, all posted messages, as did Everton midfielder Steven Pienaar, who wrote: "Big happy birthday to my hero TaTa Madiba."
Golfer Gary Player recalled that a humorous and humble Mandela once asked him at a meeting at a tournament: "Gary, do you still remember me?"
A South African football magazine put together a montage of photographs of what it called Mandela's iconic football moments, including him grinning gleefully and holding the World Cup when South Africa won the right to host, and another with former Manchester United manager Alex Ferguson.
One image, from Ethiopia and at the bottom of the collection, shows a banner hoisted by local fans during a fiercely contested recent World Cup qualifier against South Africa. Despite the intense battle on the field, the Ethiopian supporters in their striped team shirts stand in front of a huge sign that reads: "We Love Mandela!! We Will Always Be At Your Side."
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