Ronald Gonzalez's side are unbeaten since their opening league game of the campaign and continued their run with a 4-2 victory at Santos de Guapiles on Wednesday.
Marvin Angulo and Daniel Colindres scored key goals in the final quarter of an hour to lead Saprissa to their win.
With Herediano held to a 0-0 draw at home to bottom side Perez Zeledon, Saprissa's win saw them climb five points clear at the top.
The league leaders looked set for a comfortable win when they struck twice in the opening eight minutes at the Estadio Ebal Rodriguez.
Ariel Rodriguez struck in the opening minute and Kendall Waston netted soon after to give them a dream start.
Carlos Hernandez pulled a goal back for the hosts on 19 minutes, but he went from hero to villain just after the hour-mark when he was sent off.
With 10 men, Santos de Guapiles equalised through Mario Viquez on 70 minutes.
But Angulo struck on 79 minutes and Colindres deep into additional time to see the visitors to their win.
Third-placed Alajuelense also lost ground on the leaders after being held to a 1-1 draw at home to Cartagines.
Lucas Gomez's brace led UCR to a thrilling 3-2 win at Puntarenas.
Roberto Mudarra's double appeared to have second-bottom Puntarenas set to claim a share of the spoils, only to concede on 88 minutes.
Ricardo Blanco scored twice
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