On a personal note this was compounded when West Ham, the football team I follow, defeated the equally mighty Manchester City away from home to sit loftily, albeit briefly, in second place behind them in the Premier League.

At the start of the season I had visions of the Hammers starting their initial campaign as tenants in London’s Olympic Stadium next year in the Championship rather than the Premier League.

Now, who knows, it may be the Champions League. Well, we can dream.

Japan certainly did, confirming that sport thrives on tales of the unexpected.

As sporting earthquakes go, it was atop the Richter Scale. This was a team which had won only one previous World Cup match in history, hailing from a nation where sumo and sushi are far more familiar to the average Japanese than a scrum.

Indeed, the Land of the Rising Sun hasn’t experienced such a seismic shock in sport since a tubby American heavyweight boxer named James "Buster" Douglas left Iron Mike Tyson scrabbling around on his knees in the ring at the Tokyo Dome 25 years ago, like a drunk searching for a dropped cigarette butt on a pub floor.

Such sensations are the meat and drink, as well as the magic, of sport, and there have been numerous in boxing like the then Cassius Clay’s conquest of Sonny Liston, followed by the same man's defeat, as Muhanmmad Ali this time, by fellow Olympic champion Leon Spinks who was having only his seventh pro fight.

Elsewhere we recall England’s football humiliation at the hands, or rather feet, of the United States at Belo Horizonte, Brazil, in the 1950 World Cup.

The late Sir Alf Ramsey, who was to become England's only World Cup-winning manager, was once asked if he was playing in England’s team in that best-forgotten game.

“Yes,“ he sniffed. ”And I was the only one who bleedin’ was!”

Greece and Denmark becoming European football champions are among other notable giant-killing achievements.

And at Middlesbrough FC’s old ground, now a housing estate, there is a lawn with a bronze cast of an imprint of a football boot. It is a sculpture by the artist Neville Gabie and marks the exact place – just to the left of the penalty spot at the Holgate End – from where an army corporal from North Korea named Pak Do-ik struck the shot which consigned Italy to a 1-0 group stage defeat in the 1966 World Cup.

The FA Cup always springs its share of shocks. As a club reporter on a South London newspaper I covered memorable matches in which amateurs Tooting and Mitcham United ousted League clubs Bournemouth and Northampton to reach the third round where they drew with Division One Nottingham Forest before losing the replay.

And how about the Crazy Gang of Wimbledon’s conquest of Liverpool in the FA Cup final in 1988?

Elsewhere,  there was the great Sir Don Bradman being bowled out for a duck in his valedictory innings.

But have there been greater cricketing upsets than Ireland defeating both England and the West Indies in World Cup tournaments?

Then there was the "Miracle on Ice" in the 1980 Winter Olympics at Lake Placid when, deep, in the Cold War, the United States ice hockey team, largely composed of amateurs and college kids, led by coach Herb Brooks, overcame the Soviet Union 4-3, the most powerful nation on ice which had won the gold medal in six of the seven previous Games.

Maybe not quite a result in the Japan-South Africa league, but the US then went on to become Olympic champions.

In horse racing as a 150-1 outsider Foinavon was clogging along so far behind the rest of the field in the 1967 Grand National at Aintree it managed to avoid an astonishing melee at the 23rd fence where all 27 of the other horses were brought down after a stray horse caused chaos.

Foinavon skipped around the debris and raced to a 20-length victory, and a place in the history books. The 23rd fence of the National is now known as Foinavon Fence.

Tennis has witnessed many stunning upsets but surely none bigger than that this year by 32-year-old unranked Italian Roberta Vinci, who in the semi-final of the US Open ended odds-on favourite Serena Williams’ bid to become the first woman to win all four Grand Slam tennis titles in the same calendar year since Steffi Graf in 1988.

But back to rugby, where the joyful Japanese feat overshadowed what might otherwise have been the most controversial talking point of the tournament: why so many of the teams involved have veritable armies of foreign legionnaires in their ranks.

Coach Eddie Jones’ Brave Blossoms are certainly reaping the rewards from having a number of expatriate internationals moving to Japan on professional contracts. These include New Zealand-born match-winner Karne Hesketh.

He and Luke Thompson, Michael Broadhurst, Justin Ives, Michael Leitch, Hendrik Tui, Male Sa’u, all born in New Zealand, qualify on residency; as do Koliniasi Holani and Amanaki Mafi (born in Tonga) and Craig Wing (Australia). Kotaro Matsushima, born in South Africa, qualified by having a Japanese parent.

Argentina are the only team whose full squad were born in their country.

Samoa have the most foreign-born players in their squad with 13. Incredibly all are New Zealand born and qualify through having Samoan parents. A handful of them have previously represented other nations at other levels. Tim Nanai-Williams was a New Zealand Sevens international before using the Olympic loophole to switch his allegiance during the past year.

Tonga are hot on their heels with 12 of their 31-strong squad coming from outside the Polynesian kingdom. It’s alleged many of Tonga’s "foreigners" never played rugby in the country prior to senior Tests.

Wales are joint third with 11 players (more than a third of their squad) alongside Japan and Scotland, with nine of Warren Gatland’s unit born in England with James King (Australia) and Taulupe Faletau (Tonga) the two exceptions.

England have three: Mako Vunipola, born New Zealand, qualifies on residency as does Billy Vunipola, born in Australia. South African-born Brad Barritt has an English grandparent.

Tendai Mtawarira, AKA "‘The Beast" is the only Springbok from outside the Rainbow Nation. Spotted playing in South Africa as No.8 for Zimbabwe Under-18s he was snapped up by the Sharks academy and converted into a prop.

The looseness of the qualification regulations in international rugby seem to make the "Plastic Brits" Olympic controversies relatively inconsequential.

Maybe this is something the International Olympic Committee should be closely examining before rugby is included on the Olympic menu in Rio next year. 

While the stats on foreign players may be fascinating, they are not quite as fascinating as Saturday’s 34-32 scoreline.

As the estimable Woodward says: ”Underdogs can become world beaters if you truly believe.”

That’s so. Or as the Japanese say, Ah so…