(Adds more reaction)
* 'Beacon of light" extinguished
* FIFA to fly flags at half mast
* Moving tribute from boxer Ali
Dec 6 (Reuters) - Tributes poured in from across the sporting world for Nelson Mandela, who died aged 95 on Thursday, including from the International Olympic Committee, soccer governing body FIFA and a moving valediction from former boxer Muhammad Ali.
The heavyweight great said he was "deeply saddened" by the death of the former South Africa president, who had inspired everyone to break barriers and reach for the impossible.
"He made us realise, we are our brother's keeper and that our brothers come in all colours," Ali said in a statement.
"He taught us forgiveness on a grand scale. His was a spirit born free, destined to soar above the rainbows. Today his spirit is soaring through the heavens. He is now forever free."
South African rugby also paid its respects to the "miracle" performed by Mandela in uniting his country, partly through his embrace of the Springbok rugby team at the 1995 World Cup.
The Nobel Peace Prize winner won over many whites when he donned the jersey of South Africa's national rugby team - once a symbol of white supremacy - at the rugby World Cup final in Johannesburg's Ellis Park stadium.
"All of our lives are poorer today at the extinguishing of the great beacon of light and hope that led the way for our country through the transition to democracy," Oregan Hoskins, President of the South African Rugby Union, said in a statement.
"'Madiba' was a great man of vision, determination and integrity who performed a miracle that amazed the world as much as it amazed his fellow countrymen.
"Through his extraordinarily vision, he was able to use the 1995 Rugby World Cup as an instrument to help promote nation building just one year after South Africa's historic first democratic election.
"Mr Mandela was also instrumental in retaining the Springbok as the emblem for our national team at a time when a chorus of voices advocated a change of the symbol, for various reasons. It was an act of reconciliation and generosity of spirit which no one could have expected."
As news of Mandela's death spread around the world, the first of what are likely to be many gestures of respect took place at sporting events on Friday.
A minute's silence was observed before the start of the second day of the second Ashes test between Australia and England at Adelaide Oval and at the first test between New Zealand and West Indies in Dunedin.
Cricket South Africa offered its initial reaction via Twitter.
"RIP Tata Mandela. It is because of you that a represented Proteas team can express their talent across the globe," it read.
IOC President Thomas Bach hailed Mandela's role in using sport for the greater cause and called him a "true statesman".
"A remarkable man who understood that sport could build bridges, break down walls, and reveal our common humanity," Bach said in a message posted on the IOC's official Twitter handle.
World soccer body FIFA ordered flags to be flown at half mast and a minute's silence to be held before the next round of international matches.
Mandela's last major appearance on the global stage came at soccer's 2010 World Cup finals, the first to be hosted on African soil, when he attended the final in Soweto to a thunderous ovation from the 90,000 strong crowd.
FIFA president Sepp Blatter, in Brazil for Friday's draw for the 2014 World Cup, paid tribute in a statement.
"It is in deep mourning that I pay my respects to an extraordinary person, probably one of the greatest humanists of our time and a dear friend of mine: Nelson Rolihlahla Mandela," said the Swiss.
"When he was honoured and cheered by the crowd at Johannesburg's Soccer City stadium on 11 July 2010, it was as a man of the people, a man of their hearts, and it was one of the most moving moments I have ever experienced."
Former England soccer captain David Beckham, who met Mandela when the team played a friendly in South Africa in 2003, said: "We have lost a true gentleman and a courageous human being."
World number one golfer Tiger Woods also paid tribute to Mandela and recalled meeting the former South African president in 1998.
"He invited us to his home, and it was one of the most inspiring times I've ever had in my life," the American said. (Reporting by Sudipto Ganguly; Editing by John O'Brien)