Costa Rican Primera Division Review: Five-star Alajuelense extend streak
Alajuelense - who have played as much as five games less than some of their rivals due to the club's involvement in the CONCACAF Champions League - climbed to third with their latest triumph.
Oscar Ramirez's side sealed their berth in the last eight of North America's premier club competition on Thursday.
And their momentum kept on rolling in Sunday's clash at Estadio Alejandro Morera Soto.
Allen Guevara opened the scoring for Alajuelense in the ninth minute and Alvaro Sanchez doubled their advantage just before the half-hour mark.
Honduras international Jerry Palacios then converted a 77th-minute penalty before grabbing a second in the dying stages.
And there was still time for Jonathan McDonald to also put his name on the scoresheet in Alajuelense's convincing triumph.
They sit six points behind leaders UCR, who edged Belen Siglo XXI 2-1 thanks to goals from Olman Vargas and Jonathan Sibaja.
Bryan Lopez pulled a goal back for Belen but they could not find an equaliser as they dropped to second-bottom.
Cartagines are two points adrift of UCR - Daniel Quiros Perez scoring the only goal in their 1-0 success against Limon.
Uruguay - who occupy the 12th and final position in the table - conceded three times in the first half in a 4-2 loss at Perez Zeledon.
Elsewhere, Herediano toppled Santos de Guapiles 2-0 and Carmelita edged Deportivo Saprissa 1-0.