Ireland inflicted Australia's first pool stage loss at a World Cup in 16 years — and recorded its maiden win over the same opponents at the tournament in five attempts — with a 15-6 victory at Eden Park on Saturday.
Riding the back of a dominant scrum and an intensity at the breakdown, Ireland scored its points through four penalty goals — two each from substitute Ronan O'Gara and flyhalf Jonathan Sexton, who also added a drop goal.
Unless Italy can cause a similar upset, the Irish will top Pool C and likely avoid the Springboks and All Blacks until the final. Instead, the Wallabies would probably have to beat the two southern hemisphere powers just to have a chance of winning a record third World Cup.
"If they win all their games and we win the next two, we finish second and it makes things a little harder, with the opposition," Genia said. "But the whole tournament has proven that it doesn't matter who you play, you've got to lift and play well, and it's going to be tough regardless. We just have to do our best, get to the quarterfinals and step up again."
Australia coach Robbie Deans said Ireland played smarter, adapting its play to suit the opponent, conditions and referee in front of a near capacity Auckland crowd of 58,678 that bayed its support for the men in green.
Genia agreed, identifying as crucial the five scrum penalties Australia conceded and countless turnovers from a Irish pack led by its rabid back row.
"They're very good," Genia said of loose forwards Stephen Ferris, Sean O'Brien and Jamie Heaslip. "Not only did they hit the breakdowns quite well in defence, but in their ball-carrying, they got over the advantage line more often than not."
"They turned us around a little bit better," he added of the Irish performance as a whole, "played field position a little bit better and then put a lot of pressure on us through the setpiece, through the scrum and the lineout as well. That's where they got their points from, that dominance in their scrum. They got penalties and took their three points."
The Wallabies' disconsolate body language told the story at the final whistle, heads bowed and shoulders slumped. That is until the players formed a circle on the pitch to impart a few crucial messages ahead of matches against the United States on Friday and Russia on Oct. 1.
"We spoke about it out there, just keep your heads up, keep positive. Obviously learn from that," Genia said. "We weren't good enough on the day, they were better than us in a few key areas. But we'll go away, work on that and we've got to be better.
"We'll win these next two games."