It wasn't the finish that Wales U21 Coach Chris Davey had been hoping for before stepping down and it means the only victory Wales enjoyed in France was their opening triumph over Georgia. Once they got into their stride, the Pumas, creative and fast going forward, had too much on the day for a lacklustre Wales and Davey admitted it was a bad day at the office for his side.
"Unfortunately we saved our worst performance for last. We're very disappointed to finish with a match where we didn't show much," said the Welsh coach.
The Welsh pack did start the match in the ascendancy. Hooker Ed Shervington crossed early on for the first try of the game, but Argentina hit back through the boot of Santiago Fernandez and prop Francisco Gomez Kodela finally rewarded the industry of their impressive pack with a try.
Another Fernandez penalty put them ahead and Benjamin Urdapilleta's effort just before the break took them in nine points to the good at 16-7.
Argentina began the second half as they had ended the first and when Benjamin Macome scored the match was all but settled. Wing Federico Meyrelles Torres piled on more agony for the Welsh.
Chris Davey's men never gave up though and, with Argentina down to 14 men after Matias Cortese was sent off in the 74th minute by Irish referee George Clancy, they scored a consolation try through flanker Will Jones.
IRB U21 World Championship Final Standings
02 South Africa
03 New Zealand
Wales 73 Georgia 25
Wales 3 France 32
Wales 10 Argentina 13
Wales 11 England 13
Wales 12 Argentina 28