Costa Rican Primera Division Review: Alonso scores 10th goal in Alajuelense win
Oscar Ramirez's league leaders won 2-0 at Cartagines, who finished with nine men after tempers flared late.
Armando Alonso's 28th-minute goal took him equal-top of the season's goals list with 10, level with Perez Zeledon's Fabrizio Ronchetti.
The victory was sealed late on by Johnny Acosta, but not before the hosts had Jose Leiva and Jameson Scott red-carded.
Herediano preserved their winning streak, taking it to four matches with a 2-0 home triumph over Carmelita.
Antonio Pedroza and Esteban Granados struck at either end of the first half to ensure Herediano did not lose ground on the leaders - and have a game in hand on Alajuelense.
Belen Siglo XXI's purple patch continued in mid-week, as they won away at Santos de Guapiles 2-1.
Bryan Lopez's 88th-minute goal proved to be the winner, as ninth-placed Belen Siglo XXI moved within one point of Santos - who have lost three in succession - in eighth.
Limon came from behind to deny Uruguay in a 1-1 stalemate, denying the latter the chance to move off bottom spot.