There was early-season optimism under new coach Joe Schmidt as the Wallabies whitewashed Wales and beat Georgia in a 3-0 start to the season in July.
But the 67-27 humiliation by the Pumas in the Rugby Championship has brought back the gloom that followed the Wallabies' group-stage exit from the World Cup in France.
Local media declared the Santa Fe shocker one of the "darkest days" in Australian rugby and a disaster for New Zealander Schmidt, whose appointment had been well received in the wake of Eddie Jones' brief and chaotic tenure.
It came as a massive reality check following the 20-19 win over the Pumas in driving rain at La Plata.
More pain may be in store when the Wallabies host an All Blacks side smarting from back-to-back defeats away to world champions South Africa.
The venue for the next test on September 21st is Sydney's Stadium Australia where the All Blacks have thrashed the Wallabies by at least 20 points in each of the last four matches.
It gives Schmidt little time to repair the Wallabies' battered confidence or find a solution to the glaring problems of their forward strength and physicality at the breakdown.
Australia had shown impressive creativity in attack as they raced away to a 20-3 lead against Argentina in the first half at Santa Fe.
But the game changed as the hosts asserted their superiority in the collisions and the Wallabies' scrum dissolved after starting prop Taniela Tupou went off uninjured before the break.
Quality forwards are thin on the ground in Australia but Schmidt has said his preference is to pick home-based players.
Winger Marika Koroibete was the only international-based player in the matchday squad in Santa Fe.
Schmidt may want to revisit that policy and make further efforts to bring hulking lock Will Skelton, who captained Australia at last year's World Cup, back into the fold.
Rugby Australia have a cap of three overseas-based players in Wallabies squads per tournament or series but the rule has become increasingly unpopular as the Wallabies continue to toil.
"Have we got the best 23 players in Australian rugby at the moment, or are some of them still based overseas?" former Wallabies loose forward and TV pundit Stephen Hoiles said at the weekend.
"We've always been about protecting Super Rugby because that's our product. That product isn't working for us at the moment and we're not picking from overseas."
For Argentina, most of whose players compete in Europe's top leagues, Santa Fe was another showcase of their quality following their 38-30 win in Wellington when they scored a record number of points against the All Blacks in New Zealand.
Second in the Rugby Championship table behind South Africa, Felipe Contepomi's side will be eager to test themselves against the Springboks in their next clash at home in Santiago del Estero and dispel lingering doubts about their consistency.
