Jamaican sprinter Usain Bolt defended his title as the world's fastest man Sunday, grabbing gold in the men's 100-meter race by setting an Olympic record with a time of 9.63.
Bolt, who became a household name with his gold medal win in the 2008 Beijing Games, is the first sprinter since U.S. Olympic legend Carl Lewis to defend an Olympic 100-meter title.
He overcame an unimpressive start to blow past the competition.
"My start wasn't too good but my coach always said to me I'm not a good starter, it's not worth worrying about," Bolt said after the race.
Yohan Blake, also of Jamaica, took the silver medal while Justin Gatlin of the United States won bronze. Both set new personal bests with 9.75 and 9.79 seconds, respectively.
Despite his impressive win, Bolt was looking ahead to his next race.
"It means one step towards being a legend, so I'm happy with myself, but it's only one step, I have the 200 meters to go," he said.
On the woman's side, Sanya Richards-Ross of the United States won the gold medal in the 400-meter dash. Christine Ohuruogu of Great Britain took the silver and DeeDee Trotter of the United States won bronze.
Also on the track, double-amputee sprinter Oscar Pistorius, who runs on special carbon fiber blades and is nicknamed The Blade Runner, failed to make the final in the men's individual 400-meter race. He came in nearly two seconds behind the leader in his semifinal heat.
Pistorius is the first person to compete in the able-bodied Olympics using prosthetic legs, and he will also compete in the Paralympics later this summer.
Earlier Sunday, Andy Murray cruised to a gold medal in the men's singles tennis final, beating Roger Federer in straight sets.
Three times prior, Murray had played Federer in an important final, and three times he had failed. In front of an enthusiastic home crowd, Murray flipped the script on the world's top-ranked player.
"I've had a lot of tough losses in my career, this is the best way to come back from the Wimbledon final," he told a BBC interviewer. "I was a little tired after Wimbledon, but I felt fresh on the court today."
Murray said he had expected a tough match from Federer, who just four weeks ago beat Murray for his seventh Wimbledon title on Centre Court, also the site of the Olympic final.
But after winning the first set 6-2, he broke Federer to take a 2-0 lead. He grew in confidence at that point, he said, and the rout was on.
He lost only five more games in the three-set match against the man who has won three of his 17 Grand Slam titles by beating Murray.
Just hours after his win, the Brit added to his medal count by taking silver in mixed doubles alongside Laura Robson. The pair narrowly lost to Belarus' Max Mirnyi and Victoria Azarenka, 2-6, 6-3 , 10-8.
Also on Sunday, at the North Greenwich Arena where the gymnastics competition is being held, there was a stunning result in the women's vault.
After her first attempt, world champion McKayla Maroney looked like a sure gold medal winner. But her second vault turned into heartbreak as she did something she rarely does.
She came up short on her landing and fell.
"I'm really disappointed with myself," she said. "I fell on the second vault, and I don't think I've ever even fallen in warmup here at all. It's a big shock, and it's really sad."
Maroney, who had nailed her first effort and scored 15.866, received only a 14.300 on her second.
"I was praying there was still a chance, but I didn't make my vault,' she said, "and a gold medal vaulter doesn't deserve to fall."
She tried to look on the bright side.
"All I can look forward to is the next competition coming up, and I just have to accept that I have a silver medal and that's not too bad," she said.
Romania's Sandra Izbasa won the gold with a two-vault average of 15.191.
In the women's marathon, Tiki Gelana of Ethiopia won the gold in 2:23.07. Priscah Jeptoo of Kenya was the silver medalist, and Tatyana Petrova Arkhipova of Russia was third. The race kicked off under a heavy downpour as the runners snaked around wet London streets.
"It was a great race. I really loved it. The rain makes it very interesting," Gelana said. "I love running in the rain, I have been doing that since I was a small child. I slipped in the middle of the race, and my elbow is still injured. But I didn't feel any pain during the race."
More: Get latest Olympics results on CNN's live blog
Women's boxing made its Olympic debut Sunday with a round of 16 matches in each of the three weight divisions.
Overall, China leads the gold medal count with 30 and the total medal count with 61. The United States trails with 28 gold and 60 total.
One of China's golds came Sunday in the men's badminton singles final when Lin Dan beat Malaysia's Lee Chong Wei.
Lin won the same event in Beijing in 2008, also over Lee.
"This gold again confirmed my hard work over the years, because I knew to get this again I'd have to work even harder," Lin said. "I had to sacrifice quite a lot after (Beijing) 2008 because I want to retain the title. A lot of good athletes want to have this medal. Today it's a positive for me, for my efforts and for my sacrifice."