Warren Gatland's side had been tipped as the favourites before the clash in Marseille.

But after their defeat, Argentina now progress to the last four in France to face either Ireland or New Zealand, who play later this evening.

A breakaway try by Nicolas Sanchez sealed the victory for Argentina, with Emiliano Boffelli kicking the resulting conversion to put them nine points ahead.

Joel Sclavi and Sanchez both scored late tries as Argentina triumphed in the tense battle in front of a raucous crowd at the Stade de Marseille.

Wales had led 10-0 after the first quarter of the game as flyhalf Dan Biggar scored an early try, but ill-discipline allowed Argentina back into the contest.

Boffelli wiped out that deficit with four penalties during a damaging spell either side of half-time.

Scrum-half Tomos Williams' try put Wales back in front, but Argentina prop Joel Sclavi touched down and replacement fly-half Nicolas Sanchez claimed an interception try during the closing seconds.

It all rubbed salt into a gaping Welsh wound, although the Pumas were fortunate to see lock Guido Petti avoid sanction for a shoulder-led hit on Wales centre Nick Tompkins 16 minutes from time.

Wales co-captain Dewi Lake praised his opponents, saying both sides left everything on the field.

Speaking after the game, he said: "The emotions are running high at the moment, we're gutted as a group from missing out on the final four, all the work we've done over the past four months to get to this point.

"At the start of the campaign not many people thought we'd get out of the group and we came into this game as favourites and full credit to Argentina, they left everything out there, as did we, but our accuracy let us down a bit.

"You're never going to find the words to describe the emotions, but we'll learn from this, we're a young group and we'll be here again and be better."

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Winger and player of the match, Emiliano Boffelli, said: "We knew it was going to be a difficult game but we won the match, and I'm very happy for the team.

"We needed to keep going at half-time because we were doing well, and we knew at some point the game would open for us."