London (CNN) -- U.S. hopes for gymnast Gabby Douglas to repeat her gold-winning form Tuesday were dashed as she took a tumble from the balance beam -- but it was a day of joy for her teammate Aly Raisman, as Raisman claimed bronze in that event followed by a gold in the floor exercise.
Raisman, who just missed out on a medal in the women's individual all-around, beat Catalina Ponor of Romania and Russia's Aliya Mustafina to clinch victory.
"It was the best routine I've ever done," she said. "My coach said it was the best routine he'd ever seen me do."
She took the third spot in the beam after a U.S. challenge to the initial results saw Ponor pushed down to fourth. China's Deng Linlin and Sui Lu took gold and silver, respectively, in that event.
The pint-sized Douglas swung back onto the beam to continue her routine, but the slip was too costly for her to place better than seventh.
Douglas, nicknamed the "Flying Squirrel" for her aerial agility on the uneven bars, has won a new legion of fans after her thrilling win in the women's individual all-around early in the Games, but has seen medal chances slip through her fingers since.
The 16-year-old's unfortunate mistake on the balance beam followed disappointment in the uneven bars Monday, when she came in eighth.
"It was an amazing finals with so many great competitors," she said after Monday's event. "Coming into bar finals was a big challenge for me, and I made a little mistake. Even if I would have hit a solid routine, I know I have a lower start value than the other competitors."
Victory in the men's parallel bars went to China's Feng Zhe, ahead of Germany's Marcel Nguyen in silver position and France's Hamilton Sabot..
Happy hosts crown new medals king
Great Britain celebrated eight medals Tuesday, giving it 48 for the Olympics, one more than for the 2008 Beijing Games. Team GB has won 22 golds, most since the 1908 Olympics, also held in London.
There was early disappointment for Team GB, though, as triple jumper Phillips Idowu failed to make it through the qualification round. The athlete, an east London native and Beijing silver medalist, had been the focus of much injury speculation in the run-up to the Games.
Joy and tears were in evidence in the velodrome, the scene of a moving end to two great British Olympic cycling careers.
Chris Hoy took the top spot in the men's keirin cycle race, making him the first British Olympian to win six gold medals.
"I'm in shock," Hoy told the BBC, official broadcaster for the Games. "This is just surreal, this is what I always wanted, I wanted to win gold in front of my home crowd."
Hoy, now 36, said he was 99.9% sure he would not be competing in Rio de Janeiro in 2016. "This is the perfect end to my Olympic career," he said.
But Britain's Victoria Pendleton was denied a similar fairytale ending when Australia's Anna Meares took gold in the women's track cycling sprint after a dramatic finish, leaving her with silver.
An emotional Pendleton, who retires after these Games, said, "I can't believe it's all over." But, she added, "I'm very glad to be saying it's the last time I'm going to go through this."
The silver medal capped a week of ups and downs for the 31-year-old, who was disqualified from the women's team sprint alongside teammate Jess Varnish last week but then won gold in the women's keirin.
Team GB's Laura Trott won the women's omnium, a cycling contest made up of six events. American rider Sarah Hammer had been well placed going into the final stage but slipped down the rankings.
British track cyclists have won seven golds in these Games, while those from other nations have won no more than one each.
There was also early exaltation for the home crowds Tuesday, as brothers Alistair and Jonny Brownlee of Team GB split gold and bronze between them in the triathlon, with Spain's Javier Gomez winning silver.
Thousands of flag-waving spectators had flocked to watch the competitors in the men's triathlon swim in the chilly Serpentine lake, cycle laps of the Hyde Park area and run a final grueling 10 kilometers.
Alistair Brownlee strolled over waving a Union flag as he claimed an emphatic win -- Britain's first ever gold in the event -- while Jonny Brownlee made a brave recovery to take bronze after taking a 15-second time penalty for a bungled transition between phases.
In the equestrian sphere, Britain's riders Carl Hester, Laura Bechtolsheimer and Charlotte Dujardin took the home nation's first dressage gold, after holding their German rivals to a silver and the Netherlands to bronze in the team grand prix special.
The victory, which was watched from the stands by Princess Anne, came a day after Team GB claimed gold in the team showjumping.
Golden girls of the sand look for three-peat
In women's beach volleyball the U.S. is guaranteed gold and silver.
On Tuesday, the pairs of Kerri Walsh-Misty May-Treanor and Jennifer Kessy-April Ross each won their semifinal matches.
Walsh and May-Treanor are going for a third Olympic gold.
"They were playing awesome but we made it happen," May-Treanor said of their Chinese opponents. "I'm speechless. I think we played as a unit, so I'm very happy. I had a picture in my head at the beginning of the season of how I wanted us to play, and we're living that picture, but it's not over yet."
Kessy and Ross beat Brazilians Juliana and Larissa to reach the final.
"We were always trying to prove ourselves, but with that match we don't need to do that anymore," Kessy said.
Track star overcomes injury to win 1,500 meters
As the rain came down in the buzzing Olympic Stadium, the evening session was highlighted by the men's 1,500-meter final. It turned into tactical race where the favored Kenyans faded down the final backstretch. Taoufik Makhloufi of Algeria pulled away in the final 300 meters and won easily in 3:34.08, well off the world record.
In a bit of a surprise, Leonel Manzano of the United States took the silver. It was the first U.S. medal in the event since Jim Ryun won silver in 1968.
"I've been training to the best of my ability, it was an amazing time," Manzano said. "It was the only time I've ever cried after a race."
Abdalaati Iguider of Morocco edged Matt Centrowitz of the United States for the bronze.
The top finishing Kenyan was Silas Kiplagat, who was seventh.
Makhloufi was only in the race thanks to a doctor's note that said he had an injured knee. He had been expelled from the Olympics by the governing body of track and field, which said he had not put in a real effort in 800-meter qualifying.
If one of his knees was injured, you never would have known it Tuesday.
"It was the will of God, yesterday I was out, today I was in," he said. "I have a problem with my left leg and it may need surgery."
Australia's Sally Pearson, as predicted, won the 100-meter hurdles final, but only by .02 seconds. Despite poor conditions for hurdling, she beat the United States' Dawn Harper to the line in an Olympic record time of 12.35.
"Relief was the first thing I felt and then shock," Pearson said. "I'm just going through the emotions. I really wanted this. I've worked so hard for two years. To see my name on the scoreboard, I just can't believe it."
The medal success for the Americans continued in the high jump where Erik Kynard took silver. Russia's Ivan Ukhov leapt to gold. In the other final of the night, Robert Harting of Germany won discus gold.
Tuesday morning, 100-meter champion Usain Bolt and fellow Jamaican Yohan Blake, nicknamed "the Beast," eased through in their respective 200-meter heats.
Team USA's Maurice Mitchell clinched the third heat, while France's Christophe Lemaitre clocked the fastest time of the morning to win his heat.
The women's 200-meter final will feature three runners from the U.S. -- Sanya Richards-Ross, Allyson Felix and Carmelita Jeter -- and Jamaicans Shelly-Ann Fraser-Pryce and Veronica Campbell-Brown.
Odds and ends
Team USA beat Canada 91-48 in the women's basketball to reach the semifinal and will face Australia.
In men's football at Wembley, Mexico edged out Japan 3-1 in the semifinal to reach their first Olympic final. They'll face formidable Brazil, which scored three goals for the fifth consecutive match in beating South Korea. Despite their many World Cup triumphs, Brazil has yet to win an Olympic gold.
Iran's Ghasem Gholamreza Rezaei won gold in the Greco-Roman wrestling 96-kilogram final, after defeating Russia's Rustam Totrov, and Russia's Ilya Zakharov won the men's 3-meter springboard diving final.
Meanwhile, Cameroon's head of mission confirmed that seven of the African nation's athletes have gone missing while at the London Games.
The athletes, who include five boxers, a female footballer and a male swimmer, have the right to remain in the country until November. It's not yet clear if they will seek to stay longer.
China topped the medals table as of Tuesday evening, with Team USA placed second and Team GB in third, after a series of outstanding performances that have delighted the home crowd.