LONDON The United States came out on top in track duels with Jamaica at the Olympic Games when Aries Merritt flew to victory in the men's 110 meter hurdles and Allyson Felix struck gold at her third attempt in the women's 200m on Wednesday.
In the semi-finals of the men's 200m, Jamaicans Usain Bolt and Yohan Blake both cruised through their races to set up a second and potentially historic showdown at London 2012.
The Americans captured seven of the dozen athletics medals available on Day 12 of the Games, including a gold for Brittney Reese in the women's long jump, to move within two golds of China at the top of the overall medals table.
And in an all-American women's beach volleyball final, Misty May-Treanor and Kerri Walsh won their third straight Olympic title by beating Jennifer Kessy and April Ross 2-0.
Elsewhere, Hungary claimed men's and women's canoeing titles, China completed a second successive sweep of all Olympic titles in table tennis and Steve Guerdat of Switzerland won individual show jumping gold.
French and Spanish basketball players nearly came to blows, while Italy's men knocked out defending champions the United States in volleyball and Hungary in water polo.
International Olympic Committee president Jacques Rogge gave his seal of approval to a Games which, despite poor weather, has stirred huge enthusiasm in the host nation and seen Britain achieve its best medal haul for more than a century.
"All in all I would say these are very good Games and I am a very happy man," he told reporters.
Eighty thousand spectators in the Olympic Stadium witnessed the latest instalment in a series of U.S.-Jamaican track showdowns, with the Americans this time taking the honors.
Felix, a silver medalist at the last two Olympics, lengthened her stride after the bend to beat Shelly-Ann Fraser-Pryce, the Jamaican winner of the 100m, with Carmelita Jeter of the United States taking bronze.
Veronica Campbell-Brown, bidding for a third straight Olympic 200m title, came fourth.
"It's been a long time coming. I am so overjoyed," said Felix, who was runner-up to Campbell-Brown in 2004 and 2008 and lost her world title to the Jamaican last year.
"I thought back to the disappointment in Beijing, it's been a long road, I never wanted to give up," the 26-year-old told reporters. "I've wanted it for so long. This moment is really priceless."
The men's high hurdles was another U.S.-Jamaican affair, with Americans Merritt and Jason Richardson taking gold and silver, while Jamaica's Hansle Parchment got the bronze.
"The guys were talking about closing the gap on China, I know America will get that medal haul and we will show we are the best track and field nation in the world," Richardson said.
Russia's Natalya Antyukh just held on at the line to beat American Lashinda Demus in the women's 400 meter hurdles.
Bolt and Blake comfortably won their 200m semis, both easing up sharply towards the end. Blake, nicknamed "The Beast", set the faster time of 20.01, seventeen-hundredths of a second faster than his training partner.
The pair will contest a 200m final on Thursday at which Bolt, champion in both sprints in 2008 and already the 100m victor in London, will seek the historic "double double" that he says will make him a legend.
"He's my good friend, and I think it's going to be interesting," Blake said.
Bolt said he was looking forward to the final of his favorite event and would win it "without a doubt".
American Ashton Eaton took a first day lead in the decathlon, ahead of team mate Trey Hardee and Hans Van Alphen of Belgium.
Sarah Attar became the first woman from Saudi Arabia to compete in the Olympic athletics, coming last in an 800 heat she ran wearing a white head cover.
"It is the hugest honor to be here to represent the women of Saudi Arabia. It is an historic moment. I hope it will make a difference. It is a huge step forward. It's a really incredible experience," said Attar, who also has U.S. citizenship and is a student at Pepperdine University in Los Angeles.
Compatriot Wojdan Ali Seraj Abdulrahim Shaherkani similarly bowed out at the first hurdle, lasting just 80 seconds on the judo mat last week, but the pair have been hailed as heroines by many in their homeland and around the world.
In the boxing ring, where women are competing at the Olympics for the first time, Ireland's Katie Taylor beat a Tajik opponent to set up a lightweight final on Thursday against Russia's Sofya Ochigava.
In the middleweight final, 17-year-old Claressa Shields of the United States will face another Russian, Nadezhda Torlopova, who at 33 is nearly twice her age.
The U.S. men's boxing team left the Olympics without a medal for the first time. "They weren't worth watching, every single one of them was garbage," multiple weight world champion James Toney told Reuters.
The Netherlands won a shootout with New Zealand in women's hockey to set up a final against Argentina, who beat Britain.
In basketball, Spain broke open a fierce defensive battle in the final minute to beat France 66-59 and reach the semi-finals in a bad-tempered contest that threatened to turn into a brawl.
"Everybody wants to fight for those medals. Sometimes it gets a little out of hand because emotions get involved. Nobody got hurt, that's the most important thing," Spain's Marc Gasol said.
(Additional reporting by the Reuters Olympic team; Editing by Alison Williams)