The race to be crowned world's fastest man takes centre stage at the Olympics on Sunday as Usain Bolt bids to defend his 100m title in what is being billed as potentially the quickest race in history.
After an electrifying "Super Saturday," Bolt and his rivals for the blue riband event of track and field are poised to serve up more pyrotechnics as 80,000 fans pack the Olympic Stadium.
Barring major surprises, the starting line-up for the 9.50pm (0850 GMT) showpiece could feature five men who have clocked a blistering 9.8sec or faster, including world record holder Bolt.
The Jamaican defending champion strolled through his opening heat on Saturday, but faces a menacing threat to his supremacy from compatriot and world champion Yohan Blake.
With former world record holder Asafa Powell and American duo Tyson Gay and Justin Gatlin in the field, the stage is set for a classic sprint duel.
"I am the Olympic champion and I have to show the world I am the best," Bolt, 25, in a bullish eve-of-Games statement of intent.
At the other end of the distance spectrum, the women's marathon was won by Ethiopian Tiki Gelana in the opening athletics medal of the day.
After a gruelling battle through London's streets which swept past some of the British capital's most iconic landmarks, Gelana raced home on The Mall in an Olympic record time of 2hr 23min 7sec.
Kenya's Priscah Jeptoo won the silver with Russia's Tatyana Petrova Arkhipova taking bronze.
A total of 23 medals will be decided on Day Nine of the Games, where other highlights include the men's singles tennis final at Wimbledon between world number one Roger Federer and British hope Andy Murray.
Murray will attempt to add to Britain's burgeoning gold medal haul barely one month after losing to Federer on Centre Court in the final at Wimbledon.
The Scotsman also has the opportunity to win two golds in one day when he partners Laura Robson in the mixed doubles final later Sunday.
Serena Williams bagged her second gold medal of the Games following her crushing singles win over Maria Sharapova on Saturday, partnering sister Venus to take the doubles title for the third time.
The Americans beat Andrea Hlavackova and Lucie Hradecka 6-4, 6-4 to claim the gold.
China meanwhile completed a clean sweep of the badminton gold medals, with Lin Dan winning a thrilling men's singles final against veteran Malaysian rival Lee Chong Wei to retain his singles crown.
Cai Yun and Fu Haifeng then completed a five-title sweep for China in the men's doubles, downing Koo Kien Keat and Tan Boon Heong of Malaysia 23-21, 21-10.
Chinese gymnast Zou Kai successfully defended his Olympic men's floor title, denying Japanese superstar Kohei Uchimura his second gold medal of Games, while Romania's Sandra Izbasa won the women's vault.
Elsewhere, women's boxing made its debut in Olympic competition with the opening bouts in the women's flyweight and lightweight categories.
The first ever bout saw Russia's Elena Savelyeva defeat North Korea's Kim Hye-Song on points.
Ben Ainslie kept the gold medals rolling in for Britain as he won his fourth consecutive Olympic sailing title, in the Finn class -- and promptly retired.
Meanwhile, delirious British newspapers hailed the country's greatest ever day at the Olympics, with heptathlete Jessica Ennis featuring as the poster girl on all the front pages.
Ennis meanwhile confirmed Sunday she would not be taking part in the women's 100m hurdles later in the games as she prepared to take a well-earned rest.
"I'm definitely going to relax, eat lots of rubbish food, have a few glasses of wine and enjoy this moment for as long as possible," she told reporters.
