They included only two Americans, with a Frenchman, Irishman and Croatian making up the numbers. The Yanks, who so far haven't won a match, were spanked 5-0.
Perhaps part of the reason lay across the city at the O2 where the NBA game between the New York Nicks and Detroit Pistons attracted not only a sell-out crowd but several players who might otherwise have taken up boxing had slam-dunking (or grid iron) not been a better option these days.
So abysmal is fistic talent in the US that it was hardly coincidental that top American promoters Golden Boy were in London on the same day unveiling 2012 Olympic bronze winner Anthony Ogogo, 24, as their first GB Olympian signing for the Los Angeles-based organisation where he will team up with fellow former Olympic medallist Amir Khan.
Gold medallists Anthony Joshua (once he recovers from a foot operation) and Luke Campbell (providing he doesn't break a leg Dancing on Ice) will also receive substantial offers when their contracts expire with GB Boxing at the end of March.
The Yanks are certainly coming with a vengeance, Golden Boy moving in on the British scene, chequebook open and pen poised ready to buy up the best of British talent.
The reason for Golden Boy's invasion has the smack of another television reality show about it: Britain's Got Talent - and currently America hasn't. Amateur boxing in the US is down and almost out, with their National Olympic Committee having ordered an inquiry into why American boxers failed abysmally in the London 2012 Games, returning without a single men's medal (their women won two).
The only medal they secured in Beijing in 2008 was a bronze and their last gold was in Athens four years earlier, won by middleweight Andre Ward.
So far they haven't won a match in WSB and Terry Edwards, the former GB national coach whom turned down an offer to take charge of their Olympic team before the London Games told insidethegames: "The trouble is that there is no money in US amateur boxing because of their poor Olympic record. The coach education programme is rubbish. They get screwed every Olympics now because their style does not suit the present scoring system. They have some talent there but there is no one to take it to the next level. Their administration is all over the shop. Sadly in boxing terms they have become more like a Third World country."
Which is why Golden Boy have been forced to import young foreign fighters in the same manner as the Premier League recruits from overseas, with their immediate focus on buying British.
Their figurehead is the original golden boy of boxing, Oscar De La Hoya, but the man behind the move is smooth-talking chief executive Richard Schaefer a former Swiss banker instrumental in creating a boxing empire which embraces luminaries such as Floyd Mayweather Jnr, Saul Alvarez, Miguel Cotto, Bernard Hopkins, David Haye and Amir Khan.
Schaefer says he plans to stage four shows a year in this country as well as four in the US, which will feature major world title fights and young British stars. "We want to sign up some who represented Britain at the Olympics, those with the talent and charisma, who we will showcase both there and in the US. Britain is now our most important market."
Golden Boy's muscle-flexing is tantamount to a declaration of war on amateur boxing international governing body's czar, Dr C K Wu, who has instructed the word "amateur" be removed from the sport in a bid to take control of all forms of boxing.
It is also a riposte to the challenge of his baby, WSB, with its pro-style formula and prize money pot of $1 million (£630,000/€751,000).
Last week I had my first experience of the WSB at the GB-US match and like my insidethegames colleague Tom Degun, I thoroughly enjoyed the experience.
It was as good as being at a pro tournament – indeed it aped professional in almost every respect, combatants recognisable without headguards, no vests, a ten point scoring system, ring-walks, post-fight interviews and even skimpily clad round-card girls (something I have always thought boxing could do without).
GB Boxing's Matt Archibald and his team have done a terrific job in making the shows here attractive, sensibly priced, spectator-friendly affairs with special appeal to youngsters in the crowd.
The York Hall night was hosted by disc jockey and television presenter DJ Spooney who actually seemed to know a fair bit about boxing and was informative, engaging and entertaining.
As was the boxing, one of the bouts between Andrew Selby and Michael Conlon, the Olympic bronze medallist guesting for the US was as terrific a scrap as any I have seen in pro tournaments over the past year - as well as in the Olympics.
Had these brilliant bantamweights turned pro after the Olympics then such a match might not have been made for years – if at all.
No expense seemed to be spared, AIBA, flying in neutral officials from around Europe as referees and judges.
However, I do feel WSB is mistaken in allowing franchises to include overseas-born fighters. GB had two, an Estonian and an Irishman in a team of five. The Americans had three. Why? For me, foreign imports dilute the tournament and diminish national interest.
Also, the estimable but over-ambitious Wu must forget the nonsensical notion of becoming the Bernie Ecclestone of boxing. It ain't gonna happen, C K, and may well harm your hopes of becoming International Olympic Committee (IOC) President.
Better to concentrate on fine-tuning WSB and the planned AIBA Pro Boxing (APB), which will allow boxers to fight professionally while retaining their Olympic status – something with which I gather several IOC members are far from comfortable.
These tournaments can only be an alternative to pro boxing – not a replacement.
There two things WSB needs if it is to be a big winner in Britain. One a more substantial TV audience than subscription channel ESPN currently provides.
The other is the recruitment of Olympic heavyweight champion Joshua, whose addition to the Lionhearts line-up would not only lift the series but also perhaps entice the BBC to dust off the chequebook.
Joshua, the hottest ticket in boxing, is said to be giving serious consideration to joining WSB in what could be a pro apprenticeship but Schaefer reckons he will persuade him and others in the GB team to take the orthodox professional route under Golden Boy's stewardship.
They will dangle a seven-figure sum in front of big Josh, such is the desperate search for a new heavyweight hope. Yet there is a snag. Joshua has a conviction for a minor drugs offence - which could prevent him from getting a visa to box in the US. Golden Boy's extensive influence might prove helpful in this direction.
No doubt, Joshua and featherweight Campbell are wisely keeping a watching brief to whether ex-teammate Ogogo will become an Oscar winner with Golden Boy.
Last Saturday night the marketable middleweight was a contestant on ITV's much-maligned reality show Splash!. The first boxer to take a dive before a fight?
Alan Hubbard is an award-winning sports columnist for The Independent on Sunday, and a former sports editor of The Observer. He has covered a total of 16 Summer and Winter Olympics, 10 Commonwealth Games, several football World Cups and world title fights from Atlanta to Zaire.