On the bus ride from the Olympic Village to Paris La Defense Arena on Friday morning (AEST), relay swimmer Brianna Throssell was given a significant challenge—competing against American legend Katie Ledecky and Canadian teenage sensation Summer McIntosh.

The 28-year-old Throssell, who has been part of Australian relay teams for over a decade, discovered on the way to the impressive multi-purpose venue that she would swim the third leg of the women’s 4x200m freestyle relay.

The Australian relay team, which included Mollie O’Callaghan, Lani Pallister, Throssell, and Ariarne Titmus in that order, triumphed in the race and set a new Olympic record with a time of seven minutes, 38.08 seconds (7:38.08). The United States finished more than two seconds behind, taking the silver medal, while China earned bronze.

Throssell entered the water 0.44 seconds ahead of China, who were in second place at the race’s halfway point. Although Ledecky surged past her Chinese competitor and posed a threat to take the lead from Throssell, the Australian held off the greatest female swimmer of all time, giving Titmus a 0.33-second lead as she took over.

From there, it was clear the Australian team was destined for gold, with the 200m freestyle world record holder powering down the pool.

In the media mixed zone, when Throssell was asked how it felt to compete against Ledecky and McIntosh, the West Australian smiled widely.

“Ho-ly!” she exclaimed.

“When I saw the lineup and realized I was racing against Summer and Katie, I was pretty nervous,” she added with a laugh.

“But I knew I just had to swim my race and do my best. If they started to catch up, I just had to hold on for dear life.

“I was breathing towards Katie in that final 50m, just trying to keep her at bay, knowing that Arnie was ready to dive in and I just had to touch the wall for her.”

Ledecky, 27, is aiming for her fourth consecutive Olympic gold in the 800m freestyle in Paris.

McIntosh, 17, secured her first Olympic gold at these Games by winning the 400m individual medley on Tuesday morning (AEST). On Friday morning (AEST), she won another gold medal in the 200m butterfly.

“It’s such an honor to race alongside these incredible athletes,” Throssell said.

“Katie is just unbelievable, and Summer, who’s already won gold tonight—competing with them is truly an honor.”

Throssell was still radiating pride as she joined Nine’s Today show about two hours after leaving the arena.

The 28-year-old confirmed that this would be her last Olympics, and thus Friday morning was her final Olympic race.

“It was my last Olympic race, so finishing with a gold medal is everything I could have dreamed of,” she said.

“I’m 28. I’m not saying my swimming career is over, but I won’t be going to LA.

“I know, and it is such an honour. Such an honour. But I know that I don’t want to be 32 and still swimming. I’m ready for the next chapter of my life.”