Paris 2024 day one RECAP: Giaan Rooney's message after Aussies win two golds and two silvers in the pool

That wraps up our live coverage of day one action from Paris.

We'll be back later on today (AEST) as day two officially begins.

The 4x100m freestyle relay was Emma McKeon's sixth Olympic gold medal, and with it, she officially surpassed Ian Thorpe as Australia's most decorated athlete.

He reckons because she's won more medals, she actually surpassed him in Tokyo.

"That was how I felt - we were equal on gold and she had one more silver or something like that," he said on Nine's coverage.

"So I counted it the normal way so I thought she was already there."

But with this gold, she is ahead in every metric.

"I couldn't think of anyone better to have that title," he said.

Given the depth of the Australian squad, and the emergence of superstars like Mollie O'Callaghan and Ariarne Titmus who each already have three gold each, he believes it's only a matter of time before McKeon is surpassed.

"It may be a title only for now ... there's some young swimmers that are swimming exceptionally well on our swim team."

Katie Ledecky was widely expected to be Ariarne Titmus' closest challenger in the women's 400m freestyle final, with Summer McIntosh a bit of a wildcard.

In reality, McIntosh pushed Titmus the whole way, and Ledecky was effectively nowhere.

Ian Thorpe said he thought this would be the case from the get-go.

"I actually thought it would be this way," he said for Nine.

"I thought Summer McIntosh was the great unknown and watching her this morning doing the analysis, looking at how athletes have been swimming, Summer McIntosh was the hardest athlete for me to read this morning.

"When she was matching Arnie early this the race, it was concerning.

"So Arnie didn't have the whole race her own way and Katie Ledecky was a little bit off her best time."

Aussie swimming legend Giaan Rooney said Australia's gold rush in the opening night in the pool could inspire and lift the rest of the Aussie team for the rest of the week.

Ariarne Titmus defended her 400m freestyle crown, and the Aussie girls won their fourth-straight gold in the 4x100m freestyle relay.

"Wasn't it just magnificent," Rooney said on Nine's coverage.

"We hoped for this, we really hoped for it (and) we got it. This was just an epic poolside night.

"It sets off the domino effect, a night like this inspires the rest of the team and the rest of the performances.

"The first domino has fallen, bring on the rest."

Ian Thorpe said everyone gets a lift because of how close-knit the entire Dolphins squad is.

"There is a level of confidence that in the preparation that everyone is doing," he explained.

"We are swimming well, we are happy and we know that we can do it as well.

"We've been in the same training camp together, the same squad and you have knowledge, and an awareness.

"It just brings something out in you. It gives you that little bit extra and more that can only happen at an Olympic Games."

An era-defining winning streak in Olympic fencing was snapped in a shocking upset as Hungarian fencer Aron Szilagyi lost his opening bout while chasing a fourth consecutive gold medal.

Oh Sanguk of South Korea went on to win the men's saber gold with a 15-11 victory over Fares Ferjani of Tunisia in the final.

Szilagyi won Olympic gold in men's individual saber in 2012, 2016 and 2021 - the only male fencer to be a three time individual champion.

In Paris, he was trying to become the only fencer in Olympic history with four individual gold medals.

Instead, the streak ended in Szilagyi's first bout of the Paris Games, where he was beaten 15-8 by the 27th seeded Fares Arfa in the round of 32 for one of the biggest upsets so far at the 2024 Olympics.

Amid that swimming mayhem, Emma McKeon has moved further up the swimming pantheon with her sixth gold medal coming as a member of Australia's remarkable 4x100m freestyle relay team.

Incredible achievement.

"Wow. I don't keep track of that kind of stuff ... it's an honour really," she told Nine.

"To be part of this (4x100m relay team), it's extremely hard and this is a team of six with Bronte (Campbell) and Liv (Olivia Wunsch, heat swimmers) - we couldn't do it without this group of six.

"Everyone wants to be part of this team. I feel really honoured to be part of it.

Katie Ledecky has six individual golds, the most of any female swimmer in Olympic history.

"It's always good to get a medal for Team USA," Ledecky said after winning bronze in the 400m freestyle.

"I want to be a little faster, but I can't complain with the medal."

Ariarne Titmus is all class in paying homage to great rival Katie Ledecky after beating the American in the 400m freestyle final.

"I'm just happy to get the result for myself and I feel so honoured to be a part of the race and be alongside legends like Katie," Titmus said.

"I look up to her so much as an athlete and it's certainly not a rivalry beyond the races. I really respect her as a person."

Titmus will now refocus for a shot at more gold in the 200m freestyle.

"My legs are a bit tired, but I'm just relieved more than anything," the Australian said.

"I probably felt the expectation and pressure for this race more than anything in my life, to be honest, and I'm pretty good at handling the pressure of it. I hope that we put on a good show tonight and everyone enjoyed it."

Relay star Shayna Jack has a gold medal around her neck, completing a true comeback story after her doping ban and very public personal struggles.

"I can't imagine and there's very few people that would ever happen to," Ian Thorpe says on Nine.

"Most people would have probably given up, if they had faced the same circumstances as Shayna."

The Australian 4x100m women's relay team are about to receive their gold medals as Tom Cruise watches on in Paris.

It's four straight golds for Australia in this event.

"Dominant... I keep on using this word for this Australian team. I don't think there is a more dominant Australian team in any code, any sport," Ian Thorpe says on Nine.

"Please tell me if there is one. Happy to be wrong on it."

Kyle Chalmers storms home to win Australia silver as the USA take gold in the 4x100m men's freestyle relay final.

Heck of a swim by Chalmers as Kai Taylor also swum a strong third leg.

Italy took bronze.

"I do not think we could have wished to hope for anything better than that. That was an exceptional swim," Giaan Rooney says on Nine.

What a sensational session this is for Australia, living up to the lofty expectation.