Having finished fourth in their heat, the team of Jess Thornton, Anneliese Rubie, Caitlin Sargent-Jones and Morgan Mitchell missed an automatic qualification berth for the final, and had to wait to see if their time of 3:25.71 would claim one of the last two spots.

Teenager Thornton described the tension as the team watched the conclusion of the second heat.

"[It was a] bit nerve-racking," Thornton said.

But Germany - who finished fifth in heat two - could only muster 3:26.02, and Australia were through. Cue delirium, with the screams eminating from the tunnel clearly audible in the mixed zone.

"I think we all just saw the last two numbers instead of the middle two which was 26, and were all a little bit worried for that slight second, and then we realised it was 26 and we just screamed as loud as we could because we realised we'd made the final."

It is the first time Australia has made the final since 2000.

For Mitchell it was some form of consolation after the disappointing of her last placing in her 400m semi-final earlier in the meet.

"I had to redeem myself I guess. I had a few dark days after the semis so I thought let's just get back into the groove of things and make that final. We did that so I'm really happy.

"Jess Thornton as a roomie's been amazing. She just said 'stay positive. The past is in the past and let's look forward.'"

Mitchell also said she had recieved support from 2000 Olympic gold medallist and mentor Cathy Freeman - who was in the 2000 relay team.

"You're 21, we've all failed, if other people can't understand it that's their problem," was the message from Freeman according to Mitchell.

Australia could consider making a change for the final - with Lauren Wells an option for the race on Saturday night (Rio time).