Across New Zealand there is general agreement: failing to win the World Cup would be grim but losing in a semi-final to Australia would be even worse. No wonder the Wallaby camp sound so quietly optimistic ahead of Sunday's game, regardless of the possible absences of Kurtley Beale and Pat McCabe. They know virtually all the pressure is on the host nation.

Even five days before the game reporters from the Auckland Herald have been asking psychologists how All Black supporters can best brace themselves for potential disaster. "Stay calm" and "Block incoming calls starting with +61" were among the suggestions but, in the end, it will come down to how successfully New Zealand's players maintain their composure. As the scrum-half Will Genia put it: "Obviously there's a lot of public expectation and that might work in our favour."

The under-rated Wallaby centre Adam Ashley-Cooper also stressed how much strength his own team have gained from the backs-to-the-wall victory over South Africa in Wellington. "We can take a lot of positives out of it in terms of the character and the courage we showed. We didn't have any possession and we topped the tackle count but we still won," said Ashley-Cooper, who may have to be redeployed in the back three if Beale's hamstring problem does not improve fast.

His team-mate Genia went even further, suggesting he is "100% confident" the Wallabies can score their first win at Eden Park since 1986. "I don't know if I could be more confident. I'm not cocky or arrogant, but I really believe in the guys that we have in this group that we can do it. We back each other all the way and we showed on the weekend we can not only win through skill but also team spirit, wanting to do it for each other. If you look at the stats alone, you'd think they beat us 50-0 ... it was just won on guts and character. For that fact alone, I have every confidence going into this game."

There is also a collective Wallaby belief that Quade Cooper, their mercurial playmaker, will come good when it matters. Cooper has copped all sorts of stick at this tournament but Anthony Faingaa, who has played with the fly-half since his school days, is adamant he will bounce back from his uncomfortable performance against the Springboks: "Quade's never had two bad games in a row. Ever." Ironically, the All Blacks backs assistant coach, Wayne Smith, feels similarly. "He has played pretty well against us. He is mercurial, he is dangerous ... if he has a real good day then you are in trouble. Quality players come right pretty quickly."

Ashley-Cooper stresses it is up to those around Cooper to share some of the load. "He's an important member of the squad – all 10s are instrumental and he's a director of our team. He sees a lot of our ball and a lot of the pressure comes through him. We've got to support him better and that's something we've addressed. A lot of people here in New Zealand are against Quade but at this level you've got to embrace that and accept that pressure."

Should Beale fail to recover, as sources close to the team suggest is a strong possibility, the most obvious option would be to use James O'Connor at No15 and bring in Lachie Turner on the wing, possibly opposite Sonny Bill Williams if New Zealand opt to start the big man. Ashley-Cooper will be as interested as anyone else to see whether Graham Henry goes down that particular route. "He hasn't played much international football on the wing but what he lacks in positional awareness he certainly makes up for in physicality and presence. He has the strength to get over the advantage line ... it's not about creating something special, brilliant or extraordinary. It's about doing the basics well and Sonny Bill does that."

Australia are rather more optimistic their prop Sekope Kepu will recover from an ankle problem as the Wallabies seek to make their third final in the past four tournaments. "It's the biggest game of everyone's career in this squad and we're all excited by that. It's going to be a great occasion: Eden Park, full house, World Cup semi. What else do you want in life?" asked Ashley-Cooper rhetorically, insisting he and his colleagues were determined not to waste last week's hard yakka. "As an Australian, we've done that too often. History shows we've struggled to back up good performances so we won't be looking back too much."