Saprissa scored twice in the final quarter of an hour to triumph on Sunday, storming straight to the top of the Primera Division standings on goals scored.
The capital club won the Torneo de Verano last season to finish the 2013-14 campaign in Costa Rica's top tier and restarted the new term with a victory in an action-packed game.
Pumas Generalena - who were promoted from the Liga de Ascenso after last season - stunned their hosts in the ninth minute at the Estadio Nacional de Costa Rica when Asdrubal Gibbons got on the scoresheet.
David Ramirez equalised 10 minutes later for Saprissa but the visitors led at half-time courtesy of Aaron Navarro's 35th-minute strike.
But Saprissa fought back after the break with Daniel Colindres levelling proceedings in the 58th minute before the home side claimed the lead for the first time in the match 19 minutes later.
David Guzman put Saprissa in front and Diego Estrada confirmed the win in the second minute of stoppage time as Ronald Gonzalez's men recovered to claim three points.
Saprissa lead Cartagines and Carmelita on goals scored with all three teams on plus-two goal difference, following the first weekend in the Primera Division's Torneo de Invierno.
UCR and Alajuelense also won their opening games of the season but trail the top three due to goal difference.
Alajuelense, who won the Torneo de Invierno last season, started their campaign with a 1-0 victory over Santos de Guapiles, while UCR defeated Perez Zeledon 3-2.
Cartagines claimed second position in the standings with a 3-1 triumph over Uruguay with Jameson Scott and Pablo Herrera scoring in the final 15 minutes to clinch the three points, while Carmelita began the round with a 2-0 victory against Limon on Friday, while Herediano drew 1-1 with Belen Siglo XXI on Saturday.
