The "fatal error" that cemented Sharn's position as runner-up on Survivor.

When Sharn Coombes chose to bring Shane Gould to the Australian Survivor final two with her, she sealed her place as runner-up.

With five votes to four, the Australian Olympic champion was crowned Sole Survivor by her fellow contestants, defeating criminal barrister Sharn to take home $500,000.

Earlier, Shane, Sharn and third place Brian Lake battled it out in a nailbiting final immunity challenge, all playing for a guaranteed spot in the final two and a chance to plead their case to the jury.

They each had to stand on poles in the sea, balancing precariously and not taking their feet or hands off – not even for a second. One wrong move and they’d be out.

Shane, 61, was the first out of the challenge, asking to get down after an hour on her pole.

From there, Brian, 36, was visibly struggling. With sweat dripped down his face, Brian reached to take his hat off and then realised his mistake – he had taken his hand off the pole and lost the challenge.

Sharn, 41, won immunity and got to decide who she’d take to the final two with her.

This is where the jury, and many viewers, think she cemented her position as runner up.

She chose to face off in the final two with close ally Shane.

In casting her vote for Shane, contestant Fenella called Sharn’s decision an “enormous mistake” choosing Shane, who was well-liked, over unpopular Brian.

Viewers agreed.

sharn $500k mistake take brian and would of been easy win #SurvivorAU

— toby nash (@Nashii1232) October 9, 2018

So it looks like the “big mistake” from the promo was actually Sharn taking Shane to the final 2 opps! #survivorAU

— Cara (@destinynz_) October 9, 2018

Sharn, you’ve made a huuuuuuge mistake taking Shane to the final. #SurvivorAU

— Andy Hanley (@inandysview) October 9, 2018

it’s clearly a no brainer or should I say no Brianer who #Sharn should take to the jury as no-one is going to want to give #Brian the title #SurvivorAU

— kingcat (@aggiepuss44) October 9, 2018

#SurvivorAU fatal error not to take Brian to jury. Dumb, Sharn. Wats love gotta do with it .

— Zella (@Zkuy8888) October 9, 2018

Putting their case before the jury Sharn argued that she had stayed loyal to her alliance and “I never broke that trust”.

But her case was undone when her nemesis Brian reminded the jury of the role Sharn played when her ally Mat was voted out without playing his immunity idol.

“You talk about honesty and loyalty, you started a strong alliance with Mat, Steve and Shane. And you thought that Mat’s name was going to come up [at tribal council] – did you tell him?” Brian asked.

She stammered through an explanation, explaining she didn’t get an opportunity to tell Mat before tribal council.

“If Mat had told me he had an idol perhaps I would have told him I’ve heard some whispers, but I didn’t know that.”

The jury votes were read out and Sharn was crowned runner-up with four votes to Shane’s five.

Speaking to TV Week, Sharn explained why she chose to face Shane over Brian in the final two.

"The main reason for choosing Shane was that I basically have had a friendship with Shane since the start of the game, we've always been loyal to each other and we've always had each other's backs and we've always been truthful to one another," she said.

"Throughout the whole game I never lied to her at all. I respected her game, I respected the way she got to the end as well and I just felt that she was a worthy competitor. To be the best, you've got to beat the best, and I wanted to go up against Shane."

She said she was confident she could win against both Shane and Brian, but she didn't respect Brian's game-play.

She didn't take away the title of Sole Survivor or the $500,000 prize, but Sharn is pleased it was Shane who did.

"If it couldn't be me, then I am happy it's her."