Usain Bolt strolled ever closer to Olympic immortality on Wednesday as American sprinter Allyson Felix made it third time lucky to win the women's 200m crown.
Jamaican superstar Bolt - chasing an unprecedented second successive 100m-200m double - booked his place in Thursday's 200m final with an imperious semi-final victory, easing up after 100m to qualify easily in 20.18sec.
The 25-year-old, who lit up the Games on Sunday with a superb win in the 100m, warned that his 200m world record of 19.19sec could now be in jeopardy.
"It's a possibility, definitely. I can't say but the track is fast, it's going to be a good race," Bolt said. "There are going to be a lot of great competitors so I'm looking forward to it."
Bolt is bidding to become the first man in history to successfully defend both his 100m and 200m titles.
His opponents in Thursday's final will include compatriot Yohan Blake, who won his semi-final in 20.01sec, and like Bolt eased up well before the line.
The women's 200m final saw a heartwarming story as Felix finally bettered her silver medals from the 2004 and 2008 Games to claim her first gold over the distance at the third time of asking.
The 26-year-old from Los Angeles had been beaten by Jamaica's Veronica Campbell-Brown in both her previous final appearances.
But the willowy Californian glided home in 21.88sec to take gold ahead of Jamaica's Shelly-Ann Fraser-Pryce (22.09sec) and Carmelita Jeter of the United States winning (22.14sec).
Campbell-Brown, Felix's long-time nemesis who was attempting to win an unprecedented third consecutive 200m crown, trailed in fourth.
"Finally. It has been a long time coming," said Felix. "I've waited so long for this moment, for so long, and I am just overjoyed.
"I thought back to the disappointment in Beijing (where she won silver in 2008). It's been a long road, I never wanted to give up.
"It's been a journey - never easy, but you can't lose sight of your dream."
The men's 110m hurdles saw favourite Aries Merritt lead a USA one-two, clocking a season's best of 12.92 sec to take gold ahead of compatriot Jason Richardson and Jamaica's Hansle Parchment.
Russia's Natalya Antyukh won the women's 400 metres hurdles title in 52.70sec ahead of American world champion Lashinda Demus (52.77) with Czech Zuzana Hejnova taking bronze in 53.38sec.
In the only field event final on Wednesday, American Brittney Reese won the women's long jump with a best of 7.12 metres.
Away from the athletics arena, 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, who finished Day 12 on top of the medal standings with 36 golds to the United States 34, romped to a 3-0 victory 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.
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 women's flyweight competition.
Hungary celebrated their fifth and sixth gold medals 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 K4 team triumphed.
Japan's women dominated the freestyle wrestling competition, with Kaori Icho winning her third successive 63kg gold as Hitomi Obara triumphed in the 48kg category.
The star-studded USA basketball team meanwhile secured their passage to the semi-finals with a comfortable 119-86 victory over Australia. The USA will now play Argentina in the last four, while Spain take on Russia.