Wales' hopes of securing a top-four seeding in the 2015 World Cup nosedived after Argentina stunned them 26-12 at the Millennium Stadium.
Eleven years to the day following Argentina's only previous victory over Wales in Cardiff, second-half tries from wings Juan Imhoff and Gonzalo Camacho left the reigning RBS 6 Nations champions reeling.
And to make matters worse, Wales also suffered a double injury blow when centre Jamie Roberts and lock Alun-Wyn Jones departed inside the opening 40 minutes.
Full-back Leigh Halfpenny kicked all Wales' points, but they were outplayed by a Pumas team battle-hardened from recent home and away appointments with New Zealand, Australia and South Africa in the southern hemisphere's inaugural Rugby Championship.
Fly-half Nicolas Sanchez weighed in with two drop-goals, two conversions and a penalty, while veteran centre Felipe Contepomi kicked a penalty before he was forced off injured after just 10 minutes.
Wales' interim head coach Rob Howley - in charge while Warren Gatland begins preparations for heading up next summer's British and Irish Lions tour to Australia - will have been dismayed by some of his side's lethargy.
It was Wales' fourth defeat on the bounce, their first at home since last December, and leaves them with little chance of securing a top-four ranking on which top seeds will be based prior to the World Cup draw early next month.
They have Samoa, New Zealand and Australia still to come over the next three weeks, with Wales having not beaten the All Blacks since 1953 and suffered seven successive defeats at the Wallabies' hands.
And Wales' day was summed up three minutes from time when substitute back-row forward Rob McCusker burst through - but he blissfully ignored three unmarked team-mates outside him.
It was the final misguided act by Wales, with their players booed off by many in a 51,000-strong crowd.