Jamaica's Veronica Campbell-Brown competes in the women's 200m semi-finals
Jamaican sprinter Veronica Campbell-Brown will attempt an unprecedented Olympic treble on Wednesday as Usain Bolt prepares to edge closer to his second gold of the Games.
Campbell-Brown, winner of the 200m at the 2004 and 2008 Olympics, will become the first woman in history to win an individual athletics crown in three consecutive Games if she successfully defends her title.
The 30-year-old cruised into Wednesday's final with an impressive 22.32sec in her semi-final and declared herself ready to see off the threat of rivals who include Shelly-Ann Fraser-Pryce, Allyson Felix and Sanya Richards-Ross.
Campbell-Brown's opponents look more than capable of ending her eight-year reign as Olympic champion, however, and few would begrudge Felix in particular if the 26-year-old American strikes it lucky at the third time of asking.
Felix has finished as silver-medallist behind Campbell-Brown at the past two Olympics, but looked superb in reaching the final on Tuesday, coasting home in 22.31sec to win her semi-final.
The battle for the 200m crown is one of 16 medals at stake on Day 12 of the Games on Wednesday.
In addition to the 200m, women athletes will be vying for the long jump and 400m hurdles titles while men's competition sees the 110m hurdles.
Jamaican sprint king Bolt will be expected to stay on course for a repeat sprint double by booking his place in the final of the 200m following Sunday's electrifying victory in the 100m final.
The fastest man on the planet looked imperious in his opening heat on Tuesday, coasting through to the next round in 20.39sec despite virtually jogging across the line.
Meanwhile Wednesday's morning heats saw British long-distance hero Mo Farah return to the track after his gold medal in the 10,000m.
Farah secured his spot in the 5000m final with a third place finish in 13min 26.00sec, and admitted he was still suffering the after effects of his rousing win over the longer distance last Saturday.
"It was pretty difficult, pretty hard," said Farah. "The 10K took more out of me than I thought, but I've got a couple of days to recover."
South Africa's 800m star Caster Semenya left the gender controversy which once threatened her career further behind her as she finished second in her heat behind American Alysia Montano.
The 21-year-old had to undergo drug tests followed by gender tests after her 2009 World Championships victory in Berlin and was later barred from competing for nearly a year before being cleared to run again.
Away from the athletics arena on Wednesday, China added to their gold tally by completing a second consecutive clean sweep of the table tennis medals with victory in the men's team final against South Korea.
China romped to a 3-0 victory over the Koreans to claim their fourth table tennis gold of the games.
Switzerland meanwhile added their second gold of the Games as Steve Guerdat, riding Nino des Buissonnets, won the individual show jumping title at Greenwich Park. It was Switzerland's first title in the event in 88 years.
The star-studded USA basketball team will look to secure their passage to the semi-finals with victory over Australia later Wednesday.
In the boxing arena, India's five-time world champion M.C. Mary Kom was beaten 11-6 by Britain's second-seeded Nicola Adams in the semi-finals of the flyweight competition.
"My whole country was hoping for me to win a gold medal, and I am sorry I have not come back with that," said Kom, who had to move up a weight category to fight in London and finishes with bronze
Hungary meanwhile celebrated their fifth and sixth gold medals of the Games on the canoe-kayak sprint course at Eton Dorney, with Rudolf Dombi and Roland Kokeny taking the kayak K2 1000m title before their women's four triumphed in the K4 competition.