Biggest Upsets in Sport

I have been paying to much attention to the NFL to watch any games in the Rugby Union World Cup as yet but it made the news so I seeked out what high-lights I could find and have to say hats off to the Japanese defeating South Africa in the Rugby Union World Cup finals pool stage game - their first ever win and to take out a so called power house in the sport in a meaningful game - wow… such a shock that apparently no TV station back home showed the game! Any one have something that is a bigger upset as I can not think of one right now…

Japan v South Africa highlights

In terms of odds, S Africa were 1000 - 1 on to win the game with Ladbrokes. Think that must be the shortest odds ever that lost.
Other upsets that compare: USA beating England in the 1950 World Cup, Sheffield Eagles beating Wigan in the 1998 Challenge Cup final, Buster Douglas beating Mike Tyson??