Lindsay Burgoyne knows everything the 39-year-old, who grew up in Casterton, but now lives in Ballarat, has gone through just to be competing at her third Olympics.

Watching on from just outside of Noosa where he is staying for the winter, Burgoyne said watching his former charge in action was a thrill.

"It hasn't been an easy time for her," he said.

"She's had a bit of an injury coming into it which came as a bit of a surprise to me to be honest, not that she will use it as an excuse, she'll just say 'it is what it is'.

"She's one who turns off social media and things like that, so she doesn't get distracted.

"I've sent a few messages across and I know she'll get back to me when she can."

Burgoyne described Mitchell as the "ultimate professional".

"For most javelin throwers they are done by 39, but she is the ultimate professional, extremely thorough and knows her body extremely well," he said.

"She knows when she gets a niggle she knows what to do."

Mitchell was the 10th qualifier in the 12-woman final and will join fellow Australians, world champion Kelsey-Lee Barber and youngster Mackenzie Little who threw a personal best in the heats.

Mitchell only landed one throw in her heat, her second attempt which reached 61.85m.

But Mitchell has plenty of room for improvement, with her season best 63.50m thrown in June on the Gold Coast.

That throw would have been good enough to see her qualify second for the final.

Burgoyne said he always knew his former charge could achieve on the world stage, but said making three Olympic finals was an incredible achievement.

"I always knew she had the potential," he said.

"She was always extremely explosive, she was so strong and fast, she could clean 100kg, she could sprint, she was good at triple jump. These are all the components you need to be a good elite athlete particularly in javelin.

"The issue she had was that she put pressure on herself when she had up and down performances. Obviously she's matured, she's got life in perspective a lot more."

Burgoyne said he wouldn't put it past Mitchell to go on for another 12 months to compete at a fifth Commonwealth Games, where she is the reigning champion.

"She might try and stretch it for another year, depending on how her body is feeling," he said.

"I know she's finding it harder all the time, particularly in an explosive event like the javelin.

"It's the third Olympics, three Olympic finals, four commonwealth games. It wouldn't come as a big surprise if she did finish up, but you are a long time retired, she's been a full-time professional athlete since 2012."

Burgoyne, who also coached another Australian finalist Mackenzie Little said he was overwhelmed by how well the Australian team had gone.

"Mackenzie Little was a junior when I was working for Athletics Australia, was in our squad and I worked with her back then," he said.

"She's come on really well, and I'm really impressed she was able to throw a PB.

"She's achieved more than what she thought. Who knows what she'll do in the final on Friday?

"I've been very impressed with the way Australians have been going, track and field has been some phenomenal performances

"If you look at personal bests at the Olympic Games, it's a very low percentage of athletes doing that and the Australian team has been doing it all the way."

The final starts at 9.50pm.

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