Kelsey-Lee Barber's father has unwavering belief ahead of Olympic javelin final

"No big celebrations, no big party - we'll do that afterwards," said the level-headed year 4 teacher at Good Shepherd Primary School in Amaroo.

"I'm quite calm, just watch it all through and just ... try and imagine what she's feeling and channel the right vibes to her.

"It's only when she delivers - then I jump up and down and scream and shout."

Canberra's Kelsey-Lee Barber has kept contact with family back home to a minimum while competing, but Keith is assured she feels the support backing her.

"I sent her a text after she threw [in the heats], and I know she doesn't respond, but it's there, just said, 'I watched you, I know you can do this'," he said.

Left behind from an Olympic Games like no other, the families of athletes have found themselves at the centre of unprecedented attention.

It's a focus which has lifted the veil on the teams of family and friends behind athletes, whose support is crucial in the pursuit of elite careers.

Though a near-empty stadium forms the backdrop of Barber's Olympic moments, Keith has registered resounding support from the students and staff at his school, family and friends in Australia and South Africa, where he was raised.

"But what surprised me is that my school mates, that I finished school with - a long time ago - they've also all contacted me," he said.

Roberts knows his daughter well enough to see something had shifted when she stepped up for her final javelin throw in Tokyo on Tuesday.

After two shaky throws during the women's heats, Barber earned her spot in Friday night's Olympic final (9.50pm AEST) with a 62.59-metre effort - the third biggest throw of qualifying rounds. It was her biggest of the year.

"When she stepped up for that third throw, there was just something about her body language that said, 'I'm gonna do this'," Keith said.

Kelsey-Lee had plenty of support behind her on that final throw, with students from kindergarten through to year 6 watching alongside Keith at school on Tuesday.

"As a dad you know, you can support, you can love, you can put it all out there. But I've grown to a point where I can actually admire the qualities she displays," Keith said.

"And even talking to the children at school, they've picked up on it. She is inspiring, because she shows such self-discipline, the resilience, the perseverance, the dedication. All those factors are there and as a dad I see that as clear as clear."

A two-time Olympian and 2019 world champion, Barber missed the final at the Rio Olympic Games in 2016.

"The fact is, she commented back in Rio, she didn't do well and she admitted that," Keith said.

"And she said, 'I'll be back in Tokyo'. And then on Tuesday when she did it she said, 'I told you I'd be back'."

"And I believe she's gonna go one step further, and that's all we can hope. I'm incredibly proud of her and she knows that."

But the biggest question posed to Kelsey-Lee veers away from her role on the Olympic stage, to her starring role in an ad for Australian beef.

People ask about the ad, which saw her tussle with her (fake) brother for the last piece of meat at dinner, "all the time", Keith said.

"The question I get asked is, 'Who's my son? Where's my son? I didn't know you had a son'?" Keith said.

"We don't have a son, I just have another beautiful daughter."

Women's javelin final: Live from 9.50pm tonight on Channel 7 and 7plus.

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