Buenos Aires - The Jaguares adapted much better than the Bulls to the wet conditions in Buenos Aires on Saturday and finished 27-12 winners in their Super Rugby match.
Ahead from the 17th minute when centre Matias Orlando scored a breakaway try at the Estadio Jose Amalfitani, the hosts briefly surrendered the lead on the hour mark.
But the Bulls' 12-10 advantage lasted just four minutes before substitute flank Rodrigo Bruni was credited with a pushover try.
Buoyed by regaining the lead so quickly, the Argentines stretched their advantage to eight points via a penalty from flyhalf Joaquin Diaz Bonilla.
And any doubts about who would emerge victorious were dispelled with seven minutes remaining when wing Bautista Delguy scored a try which Bonilla converted.
Scoring three tries and conceding none earned the Jaguares a bonus point and lifted them from the bottom of the table to seventh place in the overall standings.
It was the first success under new coach Gonzalo Quesada after a nine-point home defeat in Round 1 by the Lions, last weekend.
Quesada was appointed during the close season when former Argentina hooker Mario Ledesma was promoted to take charge of the national team, Los Pumas.
"We adapted well to the wet conditions and deserved the victory," said Jaguares captain and centre Jeronimo de la Fuente, who succeeded Pablo Matera as leader for this season.
"Lessons were learnt from our loss to the Lions last weekend and everyone played with passion, giving the Bulls no time to settle into a rhythm."
Defeat was a severe reality check for the visitors from Pretoria, who had thrashed South African rivals the Stormers by 37 points last weekend.
The attacking flair and momentum they had on a sun-baked Pretoria pitch was nowhere to be seen on the sodden Buenos Aires field with rain falling throughout the match.
"We were confident of following up our great start to the season with another win and cannot offer the slippery conditions as an excuse," said Bulls skipper and lock Lood de Jager.
"Both sides were equally affected by the rain and the simple truth is that the Jaguares adapted much better than we did."
Bonilla, successor to France-based Nicolas Sanchez as the Jaguares' playmaker, contributed 12 points from two penalties and three conversions.
Rival flyhalf Handre Pollard slotted four penalties to retain his position as the leading points scorer in Super Rugby this season with 32.
Cornal Hendricks, debuting for the Bulls four years after being told he risked suffering cardiac arrest if he played again, was solid before being replaced in the second half.
The Bulls other wing, Rosko Specman, a two-try star in the rout of the Stormers, cut a frustrated figure as he barely touched the ball.
Jaguares15 Joaquin Tuculet, 14 Bautista Delguy, 13 Matias Orlando, 12 Jeronimo de la Fuente (captain), 11 Ramiro Moyano, 10 Joaquin Diaz Bonilla, 9 Tomas Cubelli, 8 Javier Ortego Desio, 7 Marcos Kremer, 6 Pablo Matera, 5 Tomas Lavanini, 4 Guido Petti, 3 Santiago Medrano, 2 Agustin Creevy, 1 Mayco Vivas
Substitutes: 16 Julian Montoya, 17 Juan Pablo Zeiss, 18 Enrique Pieretto, 19 Matias Alemanno, 20 Rodrigo Bruni, 21 Martin Landajo, 22 Juan Cruz Mallia, 23 Matias Moroni
15 Warrick Gelant, 14 Cornal Hendricks, 13 Jessie Kriel, 12 Burger Odendaal, 11 Rosko Specman, 10 Handre Pollard, 9 Embrose Papier, 8 Duane Vermeulen, 7 Hanro Liebenberg, 6 Ruan Steenkamp, 5 Lood de Jager (captain), 4 Jason Jenkins, 3 Trevor Nyakane, 2 Schalk Brits, 1 Lizo Gqoboka
Substitutes: 16 Corniel Els, 17 Simphiwe Matanzima, 18 Dayan van der Westhuizen, 19 Eli Snyman, 20 Thembelani Bholi, 21 Ivan van Zyl, 22 Manie Libbok, 23 Dylan Sage