No, seriously. Ireland's 15-6 throttling of Australia on September 17th is not just the biggest upset of the Rugby World Cup 2011 so far; it also shifts the balance of power.
As I mentioned in my previews, the Wallabies came into the RWC as the primary obstacle to host nation New Zealand's winning the Cup. Winning their pool - C - would allow them to enter the quarter-finals playing the second place team from pool D, which will likely be Wales, who narrowly avoided losing to Samoa 17-10 on the 17th.
Instead, unless Ireland loses its remaining matches to Russia and Italy (which is extremely unlikely), Australia will likely end up facing Tri-Nations opponent South Africa in the quarter-finals. This means the All Blacks will not have to face one of its primary opponents for the Cup at all.
The Ireland victory is also a blow for the European teams. If everything continues the way it's been going, the quarter-finals will split into Northern and Southern hemisphere brackets, with England facing France in quarter-final one, Ireland facing Wales in quarter-final two, New Zealand facing Argentina in quarter-final three, and South Africa facing Australia in quarter-final four.
The winners of quarter-finals one and two will face each other in the semi-finals, meaning we're essentially going to see a Northern hemisphere champion; at the same time, the winners of quarter-finals three and four will face each other, setting up a Southern hemisphere champion as well.
Meaning that the finals will be the best team from the North (probably France) playing the best team from the South (probably New Zealand), which seems like the way the RWC should be decided. Unless, of course, you believe that three of the best four teams in the world are Southern hemisphere teams. If the International Rugby Board had set the RWC up this way, there would have been a huge outcry. But thanks to Ireland's victory, this is now the way things are set up.
Photo courtesy of the Rugby World Cup.