Lions' coach Johan Ackermann's gamble to leave 15 first-choice players at home to prepare for the playoffs backfired with his side being knocked off top spot on the table with their loss to the Jaguares in Buenos Aires.
The South Africans had needed only a bonus point from a loss by less than seven points to clinch top spot, but after winger Anthonie Volmink's second try gave them a 22-12 lead early in the second half they were over-run by a fired-up home side.
Tries to Facundo Isa, replacement lock Matias Alemanno and a penalty try gave the Jaguares their fourth win of the season and ensured the Lions, who were reduced to 14 men twice, face the Crusaders in Johannesburg next week rather than the Sharks, who travel to Wellington to play the table-topping Hurricanes.
