Japan enjoyed a second success over America on Saturday, winning 32-17 in Tokyo's Prince Chichibu Stadium.
Having won the first Test last week Japan made it two from two against the USA Eagles on Saturday, beating them 32-17 at the Prince Chichibu Memorial Ground.
Argentina may currently occupy fourth position in the IRB World Rankings, but were they to lose to Ireland at Croke Park this weekend then they could lose that position to England, France or Wales depending on results elsewhere.
Japan defeated the United States 29-19 in the first Test of a two-match series thanks to four Ryan Nicholas penalties on Sunday.
As well as those matches profiled elsewhere, Europe's lower echelons have also been abuzz with activity over the past fortnight, and this weekend is no exception.
Japan coach John Kirwan insists the International Rugby Board must take the 2015 Rugby World Cup to Japan, in the best interests of the game.
Japan has formally applied to be the host of the 2015 and 2019 Rugby World Cups, according to an official statement issued on Tuesday.
The reaction to the recent announcement from the IRB that tendering for hosting rights to both the 2015 and 2019 Rugby World Cups has been met with a mixture of confidence and scepticism in Japan.
Samoa stole a nine-try thriller by five tries to four in a pulsating 37-31 win over Japan in the Pacific Nations Cup on Saturday.
New Zealand and South Africa will be playing for more than Tri-Nations points when they meet in Wellington on Saturday - the winners will also secure top spot on the IRB World Rankings.
New Zealand Maori swept Japan aside in Napier in the Pacific Nations Cup on Saturday, winning 65-22 courtesy of a second-half try shower that included a hat-trick from Hosea Gear.
The possibility of expanding the Super 14 and Tri-Nations competitions will be discussed when SANZAR meets with officials from five other national associations next month.
With the All Blacks having a week off, attention switches to the Pacific Nations Cup match between Japan and the unbeaten New Zealand Maori in Napier on Saturday.
Fiji fought back from a 9-3 half time deficit to beat rapidly-improving Japan 24-12 in the Pacific Nations Cup in Tokyo on Sunday.
With Japan on a high from their shock defeat of Tonga last weekend, and their cash-rich domestic league going from strength to strength, the Cheery Blossoms could not be in a better position heading into their IRB Pacific Nations Cup calsh with Fiji on Saturday.