Australian swimming star Cate Campbell has candidly revealed what went wrong with her disastrous 100m freestyle final at the Rio Olympics, while confirming she’ll be aiming for another attempt at Tokyo in 2020.

Speaking to the Seven Network, a teary Campbell said she was physically and mentally distressed the night before the 100m freestyle final, and then began the race too hard.

“Something changed at about 2am the night after the semi-final,” Campbell said. “From that moment I couldn’t eat, I couldn’t sleep.

“The nerves were just overwhelming. I think that for the first time I realised that my lifetime dream was within touching distance. I couldn’t let it go. I couldn’t relax.”

Campbell is the world record holder in the 100m freestyle, but finished sixth in the final at Rio.

She also revealed she completely bungled her tactics during the race.

“I allowed myself to panic, I spun my wheels. I went out too hard. I am not known for the back end of my races,” she said.

“I shouldn’t have front-ended like I did. As soon as my feet hit the wall I knew it would be a bloody long way home and I didn’t know if I could get that.”

Despite brilliantly winning one gold medal (4x100m freestyle) and one silver (4x100m medley) in Rio, Campbell put in a disappointing performance in her individual events.

Campbell had a diabolical individual Olympics, but excelled in two relays. Photo: Getty

She came fifth in the 50m freestyle after her 100m final flop.

Her Rio torment was symptomatic of the Australian swim team’s performance at the games.

While Mack Horton and Kyle Chalmers won individual gold, the highly fancied Campbell, Emily Seebohm, Cam McEvoy and Mitch Larkin all failed to win their pet events.

‘I’ll be in Tokyo’

Campbell said she did not want to finish her Olympic career on such a disappointing note.

“I’d always committed to swimming through to 2018 and having a home Commonwealth Games, but I can’t leave my Olympic campaign like this.

“I want to go out with happy tears not sad tears. You guys are going to have to lock me in for 2020 [Tokyo Olympics].”

But before that she’ll have to get over what happened in Rio. Campbell began the interview in tears after she watched a montage of her time at the games compiled by the Seven Network.

Campbell’s highlight in Rio was a gold medal in the 4x100m freestyle relay. Photo: Getty

“I am a little upset that I let some people down,” she said. “But more than anything else, I just … I can’t forgive myself just yet for those 60 seconds. I hoped I could have a rewrite.

“I find when I am swimming for other people and with another group of girls, and I know that I can rely on them and I know that they are going to be relying on me, I find that a liberating experience.

“[But] when I have my own expectations and my own dreams, and my own weight upon my shoulders, that I really struggle [with].”