Jamaica's Usian Bolt cemented his status as the fastest man on earth when he stormed to victory in the 100-meter dash on Sunday, while China captured five gold medals to reclaim the top spot in the medals table.

Usain Bolt has won the gold medal in the men's 100m at the London Olympic Games after winning the final in 9.63 seconds, a new Olympic record.

Bolt overcame a slow start to cross the line in an Olympic record time of 9.63 seconds, just five hundredths off his own world record at the sell-out 8,000-capacity Olympic stadium.

The 25-year-old is only the second man to win back-to-back Olympic gold medals in the blue riband event. The other athlete is Carl Lewis, who achieved the feat in 1984 and 1988.

"I was slightly worried about my start, I slipped a little in the blocks," said Bolt. "I don't have the best reactions, but I secured it and that's the key."

Compatriot Yohan Blake, who is widely tipped a serious challenger to Bolt in years to come, grabbed the silver medal in a personal best-equaling 9.76 seconds.

"To be the second-fastest man in the world behind Bolt is an honor," said Blake.

American Justin Gay, the 2004 Olympics winner who was back to action following a four-year doping ban, had bronze in a personal best 9.79.

The first final underway in the night was the women's triple jump, which was won by Kazakhstan's Olga Rypakovawon with a leap of 14.98m.

Sanya Richards Ross won the thrilling women's 400m in 49.55 seconds after holding off a strong charge from defending champion, Britain's Christine Ohuruogu, down the final straight.

There was a whiff of controversy as Ezekiel Kemboi won the 3,000m steeplechase. Kemboi, the reigning world champions, who also claimed Olympic gold in 2004, clipped fellow countryman Brimin Kipruto with around 700 meters left to run. Kipruto battled back but could only finish fifth.

In the morning, Ethiopia's Tiki Gelana won gold in the women's marathon in an Olympic record time of two hours, 23 minutes and seven seconds.

At the end of Day 9, the battle for the No. 1 position was still close with China on 30 golds and the United States on 28.

China made headway Sunday with victories in badminton, weightlifing, gymnastics and diving.

Five out of five. Chinese badminton team achieved an unprecedented clean sweep of all Olympic golds when Lin Dan outclassed old-foe Lee Chong Wei of Malaysia to retain his men's singles title and Cai Yun and Fu Haifeng triumphed in the men's doubles final.

Lin Dan of China celebrates winning his men's Singles Badminton gold medal match against Lee Chong Wei of Malaysia on Day 9

The only player to have won all nine major titles, Lin won 15-21, 21-10, 21-19 to repeat his victory over Lee in the Beijing Games final.

"There's only one Lin Dan in the world," said Lee.

Gymnast Zou Kai successfully defended his Olympic men's floor title to become the most decorated Chinese Olympian of all time. The 23-year-old now has five Olympic gold medals under his belt, surpassing table tennis legend Deng Yaping and diving queen Guo Jingjing, both of whom had four.

"This gold medal means a lot to me. I will have the stock to brag to my son in future," said Zou.

With the horizontal bar final scheduled for Monday, Zou has a chance to better his record.

The Chinese divers stayed well on track to sweep all eight gold medals as Wu Minxia and He Zi made a 1-2 finish in the women's 3m springboard diving. It was China's fifth gold out of five events.

Wu totalled 414 points from her five dives to beat teammate He Zi and Mexico's Laura Sanchez.

"I tried to give excellent execution of each move over the past three days, and I'm so glad I made a perfect ending tonight," said Wu.

Wu's victory allowed to her to draw level with Guo Jingjing as the most successful diver.

In weightlifting, China's Zhou Lulu lifted a world-record total of 333kg to take gold in the women's 75kg class.

The host nation continued its successful run on Day 9 to take its medal total to 37, including 16 gold.

Andy Murray swept aside world number one Roger Federer 6-2, 6-1, 6-4 in the men's singles final, taking sweet revenge for his Wimbledon final loss exactly four weeks ago.

"This was one of the biggest wins of my life," said Murray, who is the first British man to win the Olympic singles gold medal since Josiah Ritchie in 1908.

"This week has been incredible for me, the support has been amazing at all of the Olympic the events."

But Murray's hopes of doubles gold were smashed, when he and Laura Robson lost to Belarus' Victoria Azarenka and Max Mirnyi 6-2, 3-6, 8-10 in the final.

Britain's Ben Ainslie won his fourth consecutive sailing gold, in the Finn class, to establish himself as the sport's most successful Olympian.

Earlier in the day, Serena Williams and her sister Venus beat Andrea Hlavackova and Lucie Hradecka 6-4, 6-4 to claim their third Olympic doubles title.