The 27-year-old set a new Olympic record of 51.96sec
Australian sprint star Emma McKeon was in shock Friday after blazing to the women's 100m freestyle Olympic gold medal in the second fastest time ever, admitting her emotions were "all over the place".
The 27-year-old set a new Olympic record of 51.96sec ahead of Hong Kong's Siobhan Haughey, who timed 52.27, and fellow Australian Cate Campbell (52.52).
Only Swedish sprint star Sarah Sjostrom has ever gone faster, when she set the world record of 51.71 at the Budapest world championships in 2017. She finished sixth on Friday.
"Honestly I still can't believe i just won a gold medal. It doesn’t feel real. I can just feel like my emotions bubbling up now," said an overwhelmed McKeon.
"I feel like this week's been a bit of an emotional roller-coaster just getting up for your races and trying to relax again. So honestly, my emotions are a bit all over the place right now."
It was McKeon's fourth medal in Tokyo having already clinched gold and bronze in relays and she came third in the 100m butterfly, matching her four-medal tally from Rio.
The 27-year-old had signalled her intent in the heats Wednesday, lowering the Olympic record, with her time in the final making her and Sjostrom the only swimmers ever to breach 52 seconds.
"I've never actually won at Olympics or worlds (gold) individually, so to see that one next to my name," added McKeon.
"I didn't even look at my time, I just went for the place because that's what Olympics is about. It's getting your hand on the wall and you want that gold medal.
Haughey has been a revelation in Tokyo, with the silver medal adding to the one she sensationally won behind Ariarne Titmus in the 200m final.
She called it " crazy and surreal".
"The 200m freestyle is always my main event, so this is just a bonus," she said.
"I'm just here having a good time, and if that also means having great results it is so much fun."
The title was vacant after American defending champion Simone Manuel failed to qualify for the Games at the US trials in a shock result.
For a teary Campbell, there were mixed emotions in her fourth and likely final Olympics.
She was the hot favourite at Rio in 2016 after breaking the long standing world record in the build-up, but only finished sixth. So getting on the Tokyo podium was a relief.
"I'm so, so pleased with that performance and so pleased with that race and so proud of the week I've managed to put together," she said.
"They were understandably quite a few demons knocking at the door when I woke up this morning but I held them all at bay and performed when it counted to get another Olympic medal."