Mitchell was competing at her fourth Games and had never won a medal finishing fourth in Glasgow, fifth in Delhi and sixth in Melbourne. 

Her record throw, which was her first of the night, was the longest in women's javelin in four years. 

The 35-year-old is in the form of her life, having set the national record of 68.57m in March this year only to beat it by 35cm.

Mitchell said instead of continuously looking at results, she has looked at each throw as a good throw.

"I've started to just look at it like a good throw can come at any time when you've got six throws," she said.

"I've opened before with my biggest throw, I've also thrown my biggest throw in the last round.

"I just tried to concentrate on what I was doing in that moment, and I did that on the first throw," Mitchell said.

It had been a tough 2017 for Mitchell as she has had to change her perspective and choose to work with a new sports psychologist. 

"We've been trying to break it down into simple things, not focusing too much on results but concentrating on what I'm doing with my body," she said. 

It was an emotional win as she knew before her final throw that she had won the gold with Sunette Viljoen of South Africa throwing 57.38m. 

Mitchell's teammate Kelsey-Lee Roberts took out the silver.