In-form Alajuelense stayed top of the Costa Rican Primera Division table, despite losing, as UCR drew for the second consecutive game.
Alajuenlense's unbeaten start to the Torneo de Invierno season came to an end on Wednesday, beaten 2-0 at Belen Siglo XXI.
Oscar Ramirez's Alajuelense had won nine of their opening 10 matches prior to kick-off, but second-half goals from Jose Cancela and Ariel Santana condemned the visitors to their first defeat of the campaign.
Alajuelense (+16), who have three games in hand on rivals UCR, remain at the summit on goal difference with 28 points after UCR (+11) were held to a goalless draw by Herediano.
Deportivo Saprissa continued their surge up the table, accounting for Santos de Guapiles 1-0.
Heiner Mora's 29th-minute strike was all that separated the two teams as third-placed Saprissa made it three victories on the bounce.
Saprissa are just three points adrift of Alajuelense and UCR.
In other results, Cartagines crashed to back-to-back defeats.
Beaten at Herediano last time out, Cartagines lost 1-0 away to Perez Zeledon.
Cartagines - fourth in the table - could not find a way back into the contest following Luis Perez's ninth-minute goal.
Puma Generalena snapped a six-game winless streak, downing Limon 1-0 courtesy of Davis Vergara.
Meanwhile, basement side Uruguay and Carmelita played out a scoreless draw.