apan's upset of South Africa has justifiably been labelled the greatest upset in the history of the Rugby World Cup and probably the history of international rugby.
Just how unlikely was this result? Could we see another upset at this World Cup? And who are the likely candidates?
THE UPSET
In eight previous encounters with rugby's elite teams, Japan had never come close to a win.
Since 1983, a team outside of the International Rugby Board's tier 1 nations has met one of the traditional big five (New Zealand, Australia, South Africa, France and England) on 179 occasions for only five wins. Four of those came against France, including Tonga at the 2011 World Cup. The other was Samoa's victory against the Wallabies prior to the 2011 World Cup.
In these 179 games, the average points differential in favour of the big five team was 41 points.
Prior to beating South Africa, Japan's record against the big five was poor. Since 1983, they've played a big five team eight times and mostly lost by wide margins. They got within 19 points of Australia in 1987 and 22 points of France in 2003. In the intervening period they were handed a 145-17 thrashing by the All Blacks at the 1995 World Cup. As recently as 2013 the All Blacks cruised to a 54-6 win in Tokyo. They had never previously played South Africa.
Prior to the World Cup, South Africa's record against the minnows was unblemished: played 25, won 25. However, they did have a close-ish call at each of the previous world cups, a 13-5 win over Samoa in 2011 and a 30-25 victory over Tonga in 2007 - the year they lifted the trophy for the second time. Overall though a winning margin against teams outside tier 1 of 42.8 points per game tells the story of their dominance.
WHAT ARE THE CHANCES OF ANOTHER UPSET?
There are another eight chances for a genuine minnow to knock over a top five team in pool play at this World Cup.
Three of those will feature New Zealand against rank outsiders Namibia, Georgia and Tonga. Given New Zealand's bully boy record against minnow teams, it's virtually inconceivable that any of these games will result in an upset. The All Blacks have won by an average of 60 points against teams outside of tier 1 in the World Cup era. Only twice has a minnow team got within 20 points of them in this period.
South African fans will be very nervous when their team faces Samoa. Traditionally the strongest of the non-tier 1 teams, Samoa beat Australia in Sydney in 2011 and have taken another 10 tier 1 scalps since 1991 - including Wales four times and Scotland (who they also meet in pool play) as recently as 2012.
