Samoa are savouring their finest sporting moment after ambushing Australia 32-23 in a massive Rugby World Cup boost for the tiny Pacific Island nation.

"I can only imagine what's going on in the little island a few hours from here," jubilant vice-captain Seilala Mapusua said after Samoa outplayed the Wallabies at ANZ Stadium.

"We've always believed as a team that Manu Samoa belongs to the Samoan people, so we're always playing for our people every time we pull on that blue jersey.

"Words can't express the support we felt. Just seeing all the people waiting around at the end there, it's huge."

Samoa, population 180,000, of which most live in New Zealand, led 17-0 coming up to halftime before resisting a mini fightback from Australia to run out convincing winners.

"It's history to us, beating the No.2 team in the world," coach Fuimaono Titimaea Tafua said.

After smashing the Wallabies all afternoon, the inspired Samoans were exhausted as they desperately defended their nine-point lead in the closing 10 minutes.

"It's amazing what adrenalin can do," Mapusua said.

"Our catch cry for the week has been self-belief. I don't think we would have bothered turning up today if we didn't think we could win.

"At the end, there were guys out on their feet out there but, because of the nature of our team, guys are willing to die for their jersey.

"We know there's guys sitting on the sideline that would give their left arm to be in the position that we're in, so we're very passionate about that and I think that really carried us through in the last few minutes."

Assistant coach Brian "Aussie" McLean revealed a secret training session with Sydney University had been behind their stunning upset.

"At the start of the session, they exposed us quite a few times," McLean said.

"But as the session went on, we developed our systems and some confidence in ourselves and took it into today.

"So thanks very much to the SydneyUniversity boys."

Samoa, who are in the same World Cup pool as defending champions South Africa and Wales, could well meet Australia in the knockout stages in New Zealand in September-October.

"That's our aim," McLean said.

"Our goal is to make the quarter-finals and, the way things are set up, if we finish second in our pool and Australia wins their pool, then we would meet them in Wellington in a quarter-final.

"We had quite a good tour of the northern hemisphere last year and this was our first game where we've had all our players back.

"Now we're just hoping to grow our game and today for us was about respect. We wanted to get some respect and hopefully we've done that."

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