Pakistan, Aug. 3 -- The Americans set a world relay record and piled up three gold medals Saturday in what's been an otherwise frustrating swimming world championships for them.

And at the heart of the turnaround on the next-to-last day of the worlds in Singapore was none other than 28-year-old Katie Ledecky, the most decorated female swimmer in history.

Despite the world record in the mixed freestyle 4x100 relay - 3 minutes, 18.48 seconds - the story was Ledecky remaining unbeaten in the 800 freestyle.

She first won that race in the 2012 Olympics and has never lost since in a major competition.

Perhaps for the first time in her career, Ledecky was given only a 50-50 shot by many to beat the 18-year-old Canadian Summer McIntosh, the s...