Unbelievable upset a fantastic shot in the arm for world rugby

This is the biggest upset in the World Cup, in any sport, EVER. Or that's what it feels like for now.

Japan's victory over the Springboks is so stunning that it is almost in a league of its own. In the end, if the Springboks can regroup, it might not make a huge difference because of the way Pools A and B are set up. Japan has a chance now in the pool which includes Samoa and Scotland.

But who cares about the ramifications for now, because this is bigger then Ben-Hur as the old saying goes. This is like Daffy Duck out-running Usain Bolt, a New Zealand tennis player beating Roger Federer. This is what great international sport should be all about, and it is a fantastic shot in the arm for world rugby.

When upsets were contemplated before the tournament began, nobody would even have considered this one. Not in their wildest dreams.

The only form guide - in hindsight - was Japan's impressive burst against France during the last World Cup, when they threatened to beat the eventual 2011 finalists in their match at North Harbour Stadium. A form guide - on the other side of the coin - was the Springboks' shock home loss to Argentina and the ructions caused by the failure of South African rugby to satisfy those who are calling for faster racial transformation.

But honestly, nothing explains this result. The All Blacks would be expected to beat this Japanese side by a good 50 points. For South Africa, it should have been a cake walk. Unlike a sport such as football, heavy favouritism in rugby is harder to overcome because of the sheer physical advantages.

South Africa might not be in their finest shape, but they are one of the great sides of world rugby history, with a fully professional set of Super Rugby teams underpinning their national side. Japan can't even raise a Super Rugby side with any conviction. The Japanese have off-cuts from other nations, although their captain Michael Leitch is a class act. Leitch might be described as Kiwi, and he certainly hails from New Zealand. But he went to Japan as a 15-year-old and became captured by life there. He is very Japanese, in other words.

Yet even Leitch, a star for the Chiefs this season, did not want to play for their new Super Rugby outfit and has stayed with the Chiefs. That's how down the pecking order Japanese rugby is.