The loss, a sixth in seventh tests this year, leaves his team needing to beat Wales in their third Pool C match next weekend to guarantee they do not exit the World Cup in the opening stage for the first time.

Veteran players like Michael Hooper and Quade Cooper were left out of the World Cup squad as Australia rolled the dice on youth and Jones said setbacks had to be expected.

"Look, we've gone with a young team," Jones told reporters.

"I've got no regrets at all. We're building a team for the future, we're gonna go through some pain.

"We're doing our absolute best and I apologise. It's my fault. I take full responsibility for it."

Jones said neither captain Will Skelton, who was a late withdrawal with a calf strain, and bullocking prop Taniela Tupou, who missed the match with a hamstring issue, would be available to face Wales.

"We can't blame the loss on Skelton not being there," he said.

"We've got to be good enough to be able to cope with that."

Jones was magnanimous in defeat and praised the Pacific islanders for their performance.

"We just couldn't get one part of our game really going, if we were able to get our maul going, that could have changed the game," he said.

"We didn't get any ascendancy in the scrum and we were beaten at the breakdown."

Even the 18 penalties the Wallabies conceded did not perturb the sometimes irascible former Japan and England coach.

"When you're not on the front foot, it's quite easy to give away penalties," he said.

"So I'm not worried about our discipline, I'm worried about not getting on the front foot."

Jones took off Carter Gordon to rejig his backline as Australia chased the game in the second half but backed the flyhalf to put a disappointing game behind him.

"Carter is a young 10 and he's going to have those days," Jones said.

"But he'll bounce back. He's a good young player."

The Wallabies coach was even able to draw some positives out of the 22-15 loss, the first real upset of the World Cup.

"I was really pleased with the character the young team showed," he said.

"When Fiji is on the front foot in a fairly hostile environment, it would have been easy for our team to go away but they didn't.

"So amongst the gloom, there's some really promising things there, particularly from the younger players."