Katie Ledecky is eyeing up the 2024 Paris Olympics and the 2028 Games in Los Angeles after claiming her seventh gold medal with victory in the women's 800 metres freestyle on Saturday.

Ledecky, who holds the world record over the distance, fended off rival Ariarne Titmus for her latest swimming triumph, backing up success in the 1,500m.

The 24-year-old American was clear of Titmus throughout the race and held off the Australian's familiar late push to win in eight minutes and 12.57 seconds. Italy's Simona Quadarella claimed bronze.

Ledecky's victory takes her Olympic medal tally to 10, including the gold haul, and she is targeting more.

“I'm still young, 24 is not that old," Ledecky said. "People are sticking around in this sport into their 30s. I still love this sport, I love it more and more every year. I feel I'm going to give every ounce I have to this sport.

“I love the training, I love the day-to-day. I'm just going to keep doing it until I feel like it's time. Obviously the Olympics in 2028 are in LA so that's kind of out there and appealing also."

USA's Michael Phelps holds the record for most Olympic gold medals with 23, with the next most going to gymnast Larisa Latynina, distance runner Paavo Nurmi, swim great Mark Spitz and athlete Carl Lewis who all claimed nine golds, which Ledecky could plausibly match or eclipse.

Ledecky has already become the first US female swimmer to win three consecutive golds in the same event.

Caeleb Dressel revealed he was not feeling 100 per cent despite breaking his own world record to win the men's 100m butterfly gold medal from Kristof Milak.

American Dressel triumphed in 49.45 seconds, bettering his own mark of 49.50 from July 2019 in Gwangju, to beat Milak, with Switzerland's Noe Ponti taking bronze.

"It was well executed, my body wasn't as good as it could have been, it was the body I was given on this day, I felt better yesterday," Dressel said. "It hurt really bad but it was fine. I knew what my race plan was and stuck to it, got the job done. What a close race. Two of the fastest times in history.

"You don't get that very often so to be a part of that is very special. The event is only going to get faster. I'm aware of that and it's just exciting that it took a world record to win."

Milak also remarked after the race that the pair would push and inspire each other on to future world records.

Australian Kaylee McKeown backed up her 100m backstroke gold with victory in the 200m, ahead of Canada's Kylie Masse and compatriot Emily Seebohm.

Great Britain, powered by Adam Peaty, won the mixed 4x100m medley relay, ahead of China and Australia.

BROWNLEE TRIUMPH AS GB MAKE HISTORY

Great Britain made history by claiming the first-ever gold medal in the mixed triathlon, with victory by 14 seconds ahead of the USA.

Jonny Brownlee, who won individual bronze in 2012 and silver in 2016, opened up a good lead for the British in the second leg which they did not relinquish.

Jessica Learmonth had started off for Team GB, before Brownlee's leg, with Georgia Taylor-Brown and Alex Yee finishing it off.

"Olympics? Completed it," Brownlee said. "It feels absolutely amazing. It's my third Olympics and I've finally got gold."

Great Britain finished in 1:23:41, with France claiming bronze behind the US team.

PERFECT GROUP PHASE FOR HOCKEYROOS

Australia's Hockeyroos completed a perfect group phase after final-quarter goals from Savannah Fitzpatrick and Emily Chalker sealed a 2-0 win over Argentina.

The victory means Australia have topped Pool B with five wins from five games and will play the fourth-ranked nation from Pool A, either Great Britain, India or Ireland.

The Australia hockey team are three-time Olympic gold medallists but have not won a medal since Sydney 2000 and endured tumult in the lead-up to Tokyo 2020 with a change of coach.

China were eliminated despite beating New Zealand 3-2, while Japan also bowed out after a 4-1 loss to Spain, who finish second in Pool B.

Germany and the Netherlands meet on Saturday evening to determine top place from Pool A ahead of the quarter-finals on Monday.

SAN MARINO'S MEDAL RUSH

Tiny European nation San Marino claimed a second-ever Olympic medal, only 48 hours after grabbing their first.

Alessandra Perilli, who won bronze on Thursday in the women's trap shooting, teamed up with Gian Marco Berti to claim silver in the mixed team trap, beaten 41-40 by Spain in the final.

San Marino, which has a population of 33,600, is the least populous country to win an Olympic medal, having competed at the Games since 1960.

USA beat Slovakia 42-42 (3-2) in the bronze medal final.