Katie Ledecky beat Summer McIntosh to win a classic 800 meters freestyle final at the world championships on Saturday as the record-breaking United States hit back at their critics. On a Super Saturday for the embattled Americans, who have been struggling with illness in Singapore, Ledecky won her seventh career world gold in the event she has made her own. But the legendary American was pushed to the limit, touching the wall in a championship-record 8 minutes, 05.62 seconds, ahead of Australia's Lani Pallister (8:05.98) and McIntosh (8:07.29). It was Canadian sensation McIntosh's first defeat of the championships and ended her bid to match Michael Phelps as the only swimmer ever to win five individual golds at a single world championships. The 18-year-old has already won three golds this week in Singapore and will go for number four in the 400 meters medley on Sunday. "The feeling right now is something I never want to feel again," a forlorn McIntosh said. Ledecky, 28, had too much staying power for her younger rival, with Pallister also right in the mix until the final lunge for the line. "They pushed me all the way," said Ledecky, a four-time Olympic champion in the event. "I'm just really happy I could put that together. I just kept telling myself to trust my legs." The United States team, under the cosh after criticism from Olympic greats Phelps and Ryan Lochte, won three golds on the penultimate day of competition. They lead the medals table from Australia with eight golds following victories on Saturday for Ledecky, Gretchen Walsh and their mixed 4x100 meters freestyle relay team -- the latter in a world-record time. Walsh completed a butterfly double, romping to victory in the 50m. The American, who won the 100m butterfly earlier in the week, touched the wall in 24.83 seconds, beating Australia's Alexandria Perkins (25.31) and Belgium's Roos Vanotterdijk (25.43). Walsh said she felt "fragile" before her 100m win after coming down with a stomach bug that has swept through the American camp -- and triggered questions from Phelps and Lochte about the management of the team. She was back to full strength for the fast and furious 50 meters, which will become an Olympic event for the first time at the 2028 Los Angeles Games. "I'm very proud," said the 22-year-old, calling it a "rocky" competition for her despite the double success. She labelled the criticism from Phelps and Lochte "frustrating". To cap off a golden day for the Americans, they took gold in 3:18.48 seconds in the relay, beating Australia's previous leading time of 3:18.83 set in 2023. Australia won two golds on the night to add to their haul of seven overall. New father Cam McEvoy powered to the men's 50 meters freestyle gold to go with his Paris Olympics crown and Kaylee McKeown embellished her dominance in women's backstroke. The 31-year-old McEvoy -- who is at his seventh world championships -- reclaimed the title he won in 2023 after turning on the afterburners in the second half of the sprint to win in a sizzling 21.14sec. Britain's Ben Proud took silver in 21.26, with Jack Alexy of the United States in bronze in 21.46. McKeown added the 200 meters backstroke crown to her 100m title. McKeown again got the better of Regan Smith, touching the wall in a championships-record 2:03.33 to beat her American arch-rival into second place in 2:04.29. McKeown also won the 100-200 backstroke double at the Tokyo and Paris Olympics. France's Maxime Grousset also sealed a Singapore individual double with a rampant victory in the men's 100 meters butterfly, to complement his 50m gold. Grousset's time of 49.62 seconds was the third-fastest ever.