Australia’s Ariarne Titmus triumphed over five-time Olympic gold medallist Katie Ledecky in the women’s 400m freestyle on Monday.
In a thrilling final, the American world record holder was 0.66 seconds ahead at the half way point.
But Titmus managed to close the gap 50 metres before the finish, powering home for gold in the Tokyo Aquatics Centre.
“I can’t believe it, I’m trying to contain my emotions,” she said afterwards.
It gives the Australian the advantage in the first of three potential head-to-head showdowns between the two swimming powerhouses in Tokyo – they will face each other again in the 800m and 200m freestyle events.
There was notable joy from Titmus’ coach Dean Boxall, who celebrated wildly after her victory.
His passion sparked a big reaction on social media, with many saying he represented “all of Australia right now”.
However, a humble Titmus gave her rival much credit after her win.
“I wouldn’t be here without her,” the 20-year-old said. “She set this incredible standard. All credit to her for the swimmer she is.”
She added: “In the race I tried to stay as composed as I could and I can’t believe I pulled it off.”
Ledecky, 24, said she couldn’t be too disappointed with her performance – it was her second fastest time ever in the event.
“I couldn’t do much better than that. It was a tremendous race, a lot of fun. I felt like I fought tooth and nail and that’s all you can ask for.”
Dressel and USA relay team take gold
American talisman Caeleb Dressel led his team to gold in the men’s 4x100m freestyle relay final, cruising to victory with more than a second between them and the Italians in second.
It is the first of a potential six-medal haul for Dressel in Tokyo, who already has two Olympic golds to his name, won at Rio 2016.
He is competing in three individual events – the 50m and 100m freestyle, plus the 100m fly – and will feature in a further two, possibly three, relays.
He praised his team-mates Blake Pieroni, Bowen Becker and Zach Apple, and immediately gave his gold medal to Brooks Curry, who swam in Dressel’s place while he was rested in the heats.
“He has to hold on to it for me until he receives his medal” he told media after the ceremony.