Pablo Herrera and Roberto Segura scored second-half goals to guarantee the Ticos the Group B title and a place with Honduras in the final four of the Copa de Naciones Digicel de UNCAF.
Costa Rica is seeking a fourth straight Central American title and its victory on Sunday assured it would extend its streak of finishing no worse than fourth to all 10 UNCAF championships.
The result means Panama and Guatemala will play Tuesday for second place in Group B and the other berth in the semifinals. The third-place finisher will face off against the third-place finisher from Group A for the final berth in the Gold Cup.
Alvaro Sanchez gave Costa Rica the lead in the 34th minute but Marco Pappa equalized for Gutamela in the 51st. Herrera restored the lead in the 59th, exchanging passes with Segura before closing on goal.
Guatemala keeper Luis Molina made the initial save off Herrera's left footed shot but the rebounded to Herrera, who easily converted.
Segura added the insurance two minutes later, with some help from Guatemala defender Jaime Vides.
Segura's shot from near the top of the area, deflected off Vides thigh, changed direction and floated past Molina, who already was moving to his left.
Any chance for a Guatemala rally virtually ended midway through the second half. With Carlos Gallardo having been expelled midway through the first half for two yellow cards in 11 minutes, Carlos Castillo followed midway through the second with a straight red for a foul at midfield on Sanchez.
