Alun-Wyn Jones has braced Wales to expect a "battle-hardened" Argentina in next Saturday's autumn Test series opener at the Millennium Stadium.
While RBS 6 Nations champions Wales have not played since June, Argentina will arrive in Cardiff on the back of their debut Rugby Championship campaign that saw them tackle New Zealand, Australia and South Africa, home and away.
"Argentina are fresh from a baptism of fire in the Rugby Championship," 66 times-capped Jones said. "They will be battle-hardened and coming to Wales looking for victory, so we will have to be ready for them."
He went on: "We will definitely need to be on our guard. When you come up against these teams you have to front-up and show where you are at as a player.
"Argentina are only going to benefit from being in the Rugby Championship and playing against the best sides in the world.
"They've had a bit of a dent in their pack of late with the retirement of some key forwards, but they showed in patches in the Rugby Championship what they can achieve, and obviously playing consistently in that competition is only going to benefit them as a team."
Wales' return to action this month follows a three-Test summer tour of Australia, where they lost all three games against the Wallabies by a combined margin of just 11 points.
Those results continued a trend of narrow failures against the world's top three sides, and Jones admitted: "Australia was tough to take for us all.
"To end the series with only 11 points the difference across the three matches shows we weren't far away, but that is not good enough for us and we are determined to keep going.
"This team has reached the semi-finals of the Rugby World Cup and won the Grand Slam last season. After success like that there are always going to be tough times ahead as teams will be well-prepared for you.
"But we didn't drop off. We know we could, and should, have won any one of those games in Australia, and we are pushing the top teams in the world game hard.
"We have the top two teams in the world in our own back yard this autumn, and we have another great opportunity to make our mark."