The USA emerged as the biggest winner on the penultimate day of the swimming competition at the World Aquatics Championships on Saturday, as Katie Ledecky captured her seventh world title in the women's 800m freestyle, before the American mixed 4×100m freestyle relay squad struck gold while setting a new world record in Singapore.

In the women's 800m freestyle final, Ledecky, Canada's Summer McIntosh, and Australia's Lani Pallister quickly distanced themselves from the pack. The top trio remained neck-and-neck until the final stretch, when Ledecky pulled ahead to touch the wall first in 8:05.62, setting a new World Championships record. Pallister finished 0.36 seconds behind to take silver, while McIntosh earned bronze. China's Li Bingjie placed fifth in 8:15.59.

"That's pretty incredible, three of us going under 8:10. They pushed me all the way. I'm just really happy I could put that together," said Ledecky.

"I don't think I have anything to lose at this point of my career. Just enjoying the crowd, swimming against the best in the world. Everyone in that heat is the next generation of swimmers coming up; just proud to be a part of it," she added.

"I saw Katie swim an 8:05.62 - my goodness, that's scary fast," said Li. "I still have a long way to go to catch up with them."

Later in the evening, the American quartet of Jack Alexy, Patrick Sammon, Kate Douglass, and Torri Huske stormed to victory in the mixed 4×100m freestyle relay, setting a new world record of 3:18.48. Neutral Athletes B (NAB) snagged silver, while France claimed bronze. China did not qualify for the final.

In the women's 200m backstroke final, Australia's Kaylee McKeown topped the podium in 2:03.33, setting a new World Championships record. China's Peng Xuwei and Liu Yaxin finished fourth and sixth, respectively.

Peng, who entered the final after clocking the fastest time in the preliminaries and swam in lane four, admitted to feeling nervous at the start. "I'm not really satisfied with my splits, especially the second 50m and the final stretch. I was trying to chase back a bit at the end, but overall, it was a slow swim," she said.

Liu, the only Chinese swimmer at the Singapore Worlds to compete in both open water and indoor events, participated in the women's 10km open water race on July 16. The extended competition schedule appeared to impact her performance.

"This was a long competition for me, and it definitely affected my performance in the pool," said Liu. "For the 200 backstroke, I just gave it my all in every race. Sixth place was expected, but I'm not satisfied with the time."

In other finals, the USA's Gretchen Walsh won the women's 50-meter butterfly, Australia's Cameron McEvoy grabbed gold in the men's 50m freestyle, and France's Maxime Grousset triumphed in the men's 100m butterfly.

Semifinal action involving Chinese swimmers saw Tang Qianting rank second in advancing to the women's 50m breaststroke final, while Yang Chang placed 16th and failed to qualify. Wu Qingfeng and Cheng Yujie both advanced to the women's 50m freestyle final, after tying for the fifth-best time.

The diving competition saw China's Chen Yiwen clinch her third title at this year's World Championships, leading a one-two finish with compatriot Chen Jia in the women's 3-meter springboard final. Italy's Chiara Pellacani placed third.

Earlier in the day, China's 14-year-old Zhao Renjie topped the men's 10-meter platform preliminaries, with compatriot Zhu Zifeng also advancing to the semifinals after ranking fourth.