By Kevin Liffey and Alison Williams
LONDON (Reuters) - Andy Murray turned the tables on Roger Federer to grab tennis gold for Britain on Wimbledon's Centre Court on Sunday, four weeks to the day after Federer broke British hearts by beating him in the Wimbledon final.
The 6-2 6-1 6-4 thrashing of the world number one was the biggest win of Murray's career, and extended a dream run for the hosts that delivered six golds on Saturday, including three in the athletics stadium.
"This has been the best way to come back from the Wimbledon final," Murray said. "I watched the athletics last night ... The momentum the team's had over the last week has been so good."
Defeat virtually ended Federer's chances of completing the "golden career slam" of all four grand slam titles and the Olympic singles crown as he will be 34 when the Games moves on to Rio de Janeiro in four years.
Murray failed to add a second British gold, however, when he and Laura Robson lost to Max Mirnyi and Victoria Azarenka of Belarus in the final of the mixed doubles.
The spotlight swings back to athletics in the evening, with Usain Bolt set to answer the nagging question of whether he is still the fastest man on Earth.
The Jamaican won a golden treble with three astonishing world records at the last Olympics in Beijing. But since then he has lost his world title and his aura of invincibility.
Fans hoping the men's 100 metres final (2055 GMT) on the fast London track will top Beijing's may not have been reassured by the sight of Bolt stumbling as he qualified for Sunday's semi-final. Still, few would bet against him stepping up a gear or several.
The final is also expected to include the three fastest men in history after Bolt - Jamaica's world champion Yohan Blake, compatriot Asafa Powell and Tyson Gay of the United States - meaning Jamaica could scoop the 1-2-3 in London on the eve of the 50th anniversary of its independence from Britain.
Asked by reporters if he was in good enough shape to follow compatriot Shelly-Ann Fraser-Pryce and win back-to-back Olympic 100 titles, the usually ebullient Bolt looked down at his feet and replied: "We'll see."
Games chief Sebastian Coe described Saturday as "the greatest day in sport I have ever witnessed" after Britain took three athletics golds in less than an hour, plus two in rowing and one in the velodrome.
The home run continued on Sunday when Ben Ainslie became the most successful Olympic sailor of all time, winning the Finn class in the waters off Weymouth on England's south coast to make it one silver and four straight golds.
China also made history by claiming an unprecedented sweep of all five Olympic badminton golds as Lin Dan defeated Malaysia's Lee Chong Wei to win the men's singles title, and Cai Yun and Fu Haifeng won the men's doubles.
Serena Williams took her second tennis gold of the Games, retaining the women's doubles crown for the United States with her sister Venus after her 6-1 6-0 rout of Maria Sharapova in the women's singles final on Saturday.
It was the sisters' third Olympic doubles gold. With one singles title each, they are the only tennis players to have won four Olympic medals.
In the boxing ring, Russia's Elena Savelyeva won the first women's Olympic boxing bout in front of a packed crowd, bringing an end to the last all-male preserve at the Games.
Rejected in the past because of a perceived lack of global interest, women boxers were give a warm welcome in London when Savelyeva and North Korea's Kim Hye-song were enthusiastically clapped into the ring for the first of Sunday's 12 fights.
After winning a bout as fearsome as any of the men's fights over the first eight days, India's five-time world champion Mary Kom, one of the pioneers of women's boxing, welled up with tears of pride and relief after leaving the ring.
"I have been boxing for 12 years, I have been trying to play in the Olympic Games," she said.
"Today is very emotional, today is my twins' birthday, their fifth birthday, and I can't celebrate their birthday. But I am fighting in the ring and winning, that will be a gift for them."
The first gold of the 23 up for grabs on Day Nine was taken by Tiki Gelana of Ethiopia, who won a women's marathon that started and finished in torrential rain on a course that took in many of London's biggest tourist attractions.
"I love running in the rain," said the 23-year-old after leaving her Kenyan rivals Priscah Jeptoo and race favourite Mary Keitany trailing in second and fourth.
"The rain makes it very interesting. As soon as the race started, I said to myself 'thank God' ... I have been doing that since I was a small child."
Not everything went Britain's way. Denmark's Lasse Norman Hansen won the men's multidisciplinary omnium on the cycling track, pushing Britain's Ed Clancy into third. It was only the second of the six events in the velodrome so far where Britain have not won gold.
Hungary's double world champion Krisztian Berki broke British hearts as he dramatically snatched the Olympic pommel horse gold despite earning the same score as home favourite Louis Smith.
And in sailing, Sweden's Fredrik Loof and Max Salminen sailed a perfect medal race to beat Britain's defending champions Iain Percy and Andrew Simpson in the two-man Star class.
Also in gymnastics, Romania's Sandra Izbasa upset American favourite McKayla Maroney to strike gold in the women's vault.
In shooting, South Korean Jin Jong-oh overturned a huge deficit against compatriot Choi Young-rae and retain the men's 50-metre pistol title for his second gold of the Games.
And in women's weightlifting, China's Zhou Lulu traded world records with Russia's Tatiana Kashirina to win gold in the super heavyweight category.
The results put China back on top of the medals table with 29 golds to the United States' 27 and Britain's 16.
(Editing by Jason Neely)