Caster Semenya is aiming for Olympic glory this summer after overcoming tough times since her 2009 world title © Getty Images Enlarge 
 
 Caster Semenya says the support she has received from former South African president Nelson Mandela has served as her inspiration, and that she "feels great" as London 2012 rapidly approaches. 
 
 The former 800m world champion has experienced some harsh treatment at the hands of critics since she took gold in Berlin in 2009, with the fuss kicked up over unusually high testosterone levels resulting in a gender test and some unforgiving comments. 
 
 "With each year I experience I become more relaxed. I know now what is important to listen to and what to ignore," the 21-year-old told the Daily Mirror. 
 
 Silver at the world championships in Daegu last year came after a battle against injury, and she has struggled to get close to the 1:55.45 she clocked three years ago. However, Semenya is confident and feeling sharp heading into this summer's Games. 
 
 "If I'm at my best I feel I must win gold all the time," she said. "My friends always tell me that I'm a strong person and the best. But my head has to be clear before I run so nothing upsets me. 
 
 "Putting yourself out there takes guts. People ask questions that can make you sad. But for me I must always stay positive. 
 
 "From a young age I was a pretty good listener, a strong lady. Maybe it helped me that I never felt intimidated by anybody. Even at school I was always strong. I believed in myself." 
 
 While many questioned her achievement back in 2009 one person who congratulated her and ensured Semenya received the credit she deserved was Mandela, and he continues to serve as an inspiration. 
 
 "I never felt I would meet him. He is such a hero in South Africa. He inspired me, made me believe in what I do best," said Semenya. 
 
 "Without his support, maybe I would not be where I am today. Everything I do, I do for him." 
 
 © ESPN Sports Media Ltd. 

 Nelson Mandela celebrates 'quiet family' birthday 
 
 Mr Mandela spent the day at home and made no public appearances 
 
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 Some 12 million children across South Africa have sung a specially composed song as part of official celebrations for Nelson Mandela's 94th birthday. 
 
 It was among an outpouring of well wishes from around the world. 
 
 The former South African president is believed to have spent a "quiet" day with family at home in the village of Qunu in the Eastern Cape. 
 
 The man fondly referred to by his clan name, Madiba, now only appears rarely in public. 
 
 He spent 27 years in jail for leading an armed anti-apartheid campaign and became president in 1994. 
 
 Since his retirement from public life, the frenzy that erupts around his birthday each year has only grown - with some South Africans complaining his name has been debased by its association with a proliferation of causes. 
 
 'Favourite food' 
 
 The day began with some 12 million schoolchildren singing a birthday song including the line, "We love you father". 
 
 Throughout the day, statements were released by politicians, campaigners and union leaders - with Human Settlements Minister Tokyo Sexwale urging fellow South Africans to celebrate their fortune to "live in the same country breathing the same air under the same sun with Nelson Mandela". 
 
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 Mr Mandela's granddaughter, Ndileka Mandela, told Sowetan Live that the Mandela family would celebrate with a lunch including Mr Mandela's favourite food. 
 
 "The big lunch will be at 4pm where we will present him with a cake. Our 67 minutes is a way of giving back to him, and that is our birthday gift to him," she said. 
 
 "We will probably have food like [local corn dish] samp and tripe, his favourite food." 
 
 On Tuesday Mr Mandela met former US President Bill Clinton on Tuesday. 
 
 Mr Clinton, accompanied by his daughter Chelsea, opened a new library for the No-Moscow Primary School in Qunu, ahead of his meeting with Mr Mandela. 
 
 "When I think about Mandela I always think about someone committed to the future," Mr Clinton said. 
 
 US President Barack Obama and his wife, Michelle Obama, also paid tribute ahead of Mr Mandela's birthday. 
 
 The US first couple hailed Mr Mandela's "extraordinary life and steadfast commitment to the principles of democracy and reconciliation". 
 
 67 minutes 
 
 The BBC's Milton Nkosi in Qunu says that across South Africa, Mr Mandela's birthday is traditionally celebrated with the poor communities receiving help from those who are more fortunate. 
 
 Our correspondent says to celebrate the number of years Mr Mandela spent in public life, people are encouraged to spend at least 67 minutes of their time helping those who are less fortunate. 
 
 But some have criticised the UN-backed initiative as a token gesture used to assuage the guilt of those at the top of a deeply economically polarised society. 
 
 If Mr Mandela knew how poorly the country's schools were performing, "he would be crying", said Nobel laureate Archbishop Desmond Tutu. 
 
 Mr Mandela stood down as South Africa's president in 1999 after serving one term, handing over to Thabo Mbeki. 
 
 After leaving prison in 1990, he led the African National Congress party to a landslide victory in 1994 - the first time South Africa's black majority was allowed to vote.
– At the opening ceremony of the 2012 Olympics, the flag of South Africa will be carried by Caster Semenya, that nation's 21-year-old champion runner. Semenya receives the honor three years after the track and field governing body subjected her to a gender test, igniting a major controversy. Semnya said she drew inspiration during those days from the support she got from Nelson Mandela, notes ESPN. "Everything I do, I do for him." (Mandela, incidentally, turned 94 today, reports the BBC.)