The Jaguares rode a blistering start and an assured finish to a dominant 39-7 victory over Australia's ACT Brumbies to reach their first Super Rugby final in only their fourth season in the competition.
Steely defence, clinical finishing and a pitch perfect gameplan gave the Argentines an 11th win in their last 12 matches and a place in next week's final against either the Crusaders or Hurricanes.
Tries from scrumhalf Tomas Cubelli and lock Tomas Lavanini helped them to 20 points in the first 20 minutes as the visitors battled nerves before centre Matias Orlando crossed twice and fullback Emiliano Boffelli once in the second half.
It was always going to be tough for the Brumbies against a team boasting 14 Test players in their starting side, and a further 185 international caps on the bench.
But the visitors simply didn't turn up and looked lacklustre from the opening whistle as the 30-hour trip from Canberra to Argentina appeared to have taken a toll.
The Brumbies were riding a seven-game winning streak heading into the contest, but that scintillating form which took them to the finals was nowhere to be seen.
Brumbies hooker Folau Faingaa had his worst game of the season and lost an inconceivable five lineouts in the opening 25 minutes.
The Jaguares scored the opener after a mix up between Rob Valetini and Toni Pulu saw a kick shoot through the last line of defence and the former Brumbies player Tomas Cubelli swooped.
It proved a sign of things to come.
Joaquin Diaz Bonilla booted back-to-back penalties, both won after lost Brumbies' lineouts, as the Jaguares raced to a 13-0 lead.
The Brumbies' polish of the past two months had well and truly worn off, with the visitors making basic errors as the clinical Jaguares made the most of their chances.
The next mistake came from No.8 Lachlan McCaffrey, when he was caught isolated on the blind side and the Jaguares punched the corner from the ensuing penalty.
A few phases later and lock Tomas Lavanini barged over to score. Just like that, it was 20-0 after 20 minutes.
The Brumbies scored a crucial try through Faingaa on the stroke of half-time, but it proved a false dawn as the mistakes continued in the second half.
Brumbies skipper Christian Lealiifano tried to grubber through on 50 minutes, but it was defused by Matias Moroni who sprinted 50 metres before finding Matias Orlando to score.
Orlando scored his second after bursting through tired defenders on 62 minutes before fullback Emiliano Boffelli scored a turnover try in the dying moments.
Bonilla finished with a perfect six from six off the tee.
The nine-times champions Crusaders will host the final if they beat the Hurricanes in the other, all-New Zealand, semi-final in Christchurch on Saturday.
If the Hurricanes win, the Jaguares will have home advantage next Saturday.