Wales fly-half Dan Biggar revealed that while the team is disappointed, they will be up for the challenge of facing South Africa in the quarter-finals.
Wales had the upper-hand for periods of their clash against Australia on Saturday, but were ultimately thwarted by fantastic defence.
"We are obviously disappointed," said the Ospreys pivot.
"We've just lost a Test match in a World Cup, but ultimately we're in the quarter-finals. With the tough group that we've had and our injuries, we've got to be positive.
"We play in the quarter-finals of a World Cup next weekend and it doesn't get much better than that – 80 000 people at Twickenham against the third best team in the world.”
Biggar lamented the multiple missed opportunities to score, especially when the Wallabies were down to 13 men and Wales were camped on their line.
"Of course it feels like a missed opportunity, absolutely," added Biggar.
"During that period we were held up over the line three times. Maybe if we'd kept the ball in the scrum a little bit longer, we potentially could have had a penalty try, but it's a 50-50 call.
"Each penalty decision that was going for us was building more pressure on them and us, but they defended very well.
"We definitely should have scored a try in that period but that's the way Test match rugby is."
Biggar pointed out that Wales have enjoyed the upper hand over the Springboks in recent times ahead of next weekend's massive clash between the two sides.
Heyneke Meyer's men only just edged a touring Wales side 31-10 in Nelspruit in June last year. Then at the Millennium Stadium in November, Wales earned their first win over South Africa since 1999, winning 12-6.
"That win is huge, which is why we're very positive," added Biggar.
"Out of the southern hemisphere teams, we've got the best record against them recently. There's no denying that they'll bring a varied game and it'll be a huge, huge task to stop them. We'll go into the game as underdogs, but we're looking forward to that."