Rebecca Adlington claimed her second bronze medal of the London Olympics as 15-year-old Katie Ledecky produced the second fastest 800 metres freestyle in history to take gold for the United States.
Ledecky led from start to finish as the expected duel between Britain's Adlington and Denmark's Lotte Friis failed to materialise.
Instead, Ledecky went straight out and moved further ahead from the halfway stage, under world record pace all the way until the final metres to touch in eight minutes and 14.63 seconds, with only Adlington ever having gone faster when she set a world record in Beijing.
With 200 metres to go, Spaniard Mireia Belmonte Garcia attacked to overhaul Adlington and finish second in 8mins 18.76secs.
Adlington picked up her second third place of the week, following her 400m bronze, touching in 8:20.32.
Ledecky's gold meant the United States had won every title so far of the session.
"It was such a difficult race, she swam so fast," Adlington told BBC1. "She swam absolutely incredible. I think she's only really young as well - 15 - it's amazing.
"The 800 was my event. I think the pressure and everything, the expectation, everything going into this meet has been a little bit of a battle but I'm so pleased with that.
"I would have liked the time to have been a bit quicker, I'm not going to lie. I've done that time all year and I don't know what happened. Everything just kind of caught up with me.
"I gave it my absolute all and I'm sorry that I didn't get the gold for everyone that was expecting me to.
"But I am so proud and pleased to get a bronze medal - it's nothing ever to be embarrassed about. I hate it when people say that silver or bronze is losing because you have not done my sport.
"Swimming is one of the hardest sports to medal at. We're not like other sports. It is so, so difficult and I hope the public realise this this week and hopefully will be proud of me for getting that bronze."