Just 10 slots in the grand final were on offer, with 18 countries competing to secure one of them.

As well as Australia, the nine other countries proceeding to this weekend's hotly contested final are Moldova, Azerbaijan, Greece, Sweden, Portugal, Poland, Armenia, Cyprus and Belgium.

Going home are Georgia, Albania, Montenegro, Finland, Iceland, Czech Republic, Slovenia and Latvia.

Though the successful semi-finalists are not announced in a specific order, Australia was left on a precipice as the eighth winning country of 10 named.

In achieving the win, Firebrace navigated a number of hazards including a revolving stage which took some time to bring under control and a momentary stumble on a key high note during his performance.

Amplifying the risk, the stumbled note was repeated during a package of performance highlights which was playing during the critical voting phase of the broadcast.

But to some extent that was a self-inflicted wound as delegations usually choose which part of their song they want re-played in the package prior to the performance; the rule exists to spare organisers any accusation of sabotage.

The tripped note could have been even more costly at the preceding night's jury show; the night before the live telecast the show is run in full for the international juries to cast their votes.

Speaking to Fairfax Media backstage after the telecast Firebrace said the mounting tension as grand final slots were whittled away and Australia had still not been named was tough to endure.

"I do have to admit I was sitting on the edge of my seat a bit," the 17-year-old singer said. "But when we were announced I was over the moon and everyone around me was screaming."

During his performance, he said, he was acutely aware of the missed note.

"I did my best and despite whatever happened ... there was this high note that I went for and I didn't place it correctly," he said.

"You just have got to keep going," he said. "It would have been so much worse if I you let that affect your performance."

"When I walked off stage I was like, whatever, that happened, but I got the other notes right," Firebrace added. "I'm human, I'm not this perfect singer who sings 100 per cent perfectly.

"Now I can't wait to smash the shit out of the song in the grand final."

The competition splits the competitors into two semi-finals, with 18 countries competing in each. The 10 winners from each semi-final then enter the grand final, along with "big five" - France, Germany, Italy, Spain and the UK - and the hosting country, Ukraine.

Under the competition's rules, the "big five" - so called because they are the largest contributors to the competition's organising body, the European Broadcasting Union - along with the host broadcaster, automatically book a slot in the grand final.

The 18 countries in the second semi-final are Serbia, Austria, Macedonia, Malta, Romania, Netherlands, Hungary, Denmark, Ireland, San Marino, Croatia, Norway, Switzerland, Belarus, Bulgaria, Lithuania, Estonia and Israel.

The second semi-final will be screened live on SBS on Friday morning, Australian time.

A total of 42 countries are competing this year; the noticeable absence is Russia, who withdrew after their artist, Yulia Samoylova, was banned by Ukraine.

The SBS live telecast of the semi-final was interrupted by audio drop-outs, with portions of the commentary from Myf Warhurst and Joel Creasey not making it into the broadcast feed.

It is understood a number of commentary feeds at the venue suffered similar technical issues; the missing audio commentary will be reinstated for the prime-time replay of the semi-final.

Speaking to Fairfax Media, Creasey said that regardless of the outcome Australia had fielded such strong contenders in the past few years that it had confirmed its rightful place in the competition.

"Whatever happens we've proven we're coming to play," Creasey said.

"After Guy Sebastian, Dami Im, and now Isaiah, people know we're not sending some naff act each year.

"We are really cementing our place in the competition," Creasey added.

"Regardless of whether we're in the final or not I think we've done Australia's future in Eurovision a world of good."

Equally, Australia's participation is changing the competition by amplifying the trend among some countries to bring more legitimate, commercial pop music to the historically campy Eurovision stage.

"I think it's changing a lot, it's had a huge impact," Warhurst said. "Dami shocked everyone last year, that was noticeable and people have lifted their game."

"Among the more contemporary songs, some of it could sit quite well outside Eurovision and that's a huge difference.

"Listening to what happened in the room it's really clear, they love him, they love Australia."

Creasey said Firebrace's distinct sound gave him an edge against the competition in the first semi-final.

"He has a much more soulful voice, and it does stick out," Creasey said.

Warhurst said that the 17-year-old Riverina raised singer deserved to see the competition through to the grand final and win.

"He's the sweetest guy and he embraces that Eurovision spirit, he's young, he's beautiful and he's optimistic about life," she said.