Fixtures involving Deportivo Saprissa, Herediano and Alajuelense have been postponed with the trio missing key players, who are on national duty at the Copa Centroamericana.
Alajuelense remain just through two league fixtures - from which they have maximum points - while UCR have played five times for 13 points.
Jose Antonio Giacone's UCR took an early lead at home, Ariel Contreras netting in the ninth minute.
Santos' Ismael Fuentes then handed UCR a two-goal buffer in the 59th minute, getting the final touch into his own net.
Belen Siglo XXI triumphed for the first time this season, beating promoted Puma Generalena 3-1 at home.
Anibal Arrieta, Keilor Villegas and Leonardo Adams all netted for the eventual winners, while Luiz Gonzalez produced what would be a consolation goal for Puma in the 63rd minute.
Cartagines remained unbeaten but were held 1-1 on the road at Carmelita.
A penalty on the stroke of half-time from Daniel Quiros put the visitors ahead, and they were set to nab all three points to join UCR at the helm before a late equaliser from Carmelita's Angelo Padilla.
Limon's first away goal of the campaign helped them earn a 1-1 draw at winless Uruguay.
Cesar Lopez's 76th-minute goal cancelled out the opener from Uruguay's Seemore Johnson, taking Limon to five points from six matches and leaving Uruguay with just two points from six.
