The Central American nation, who rounded off their Group D campaign with a 0-0 draw against England earlier today, have advanced from the group stage for the first time since 1990.
Los Ticos will now face Greece on Sunday for a place in the quarter-finals of the competition, and the 61-year-old dedicated the achievement to "those who believed in us and those who didn't".
"People started believing after the game against Italy," Pinto is quoted as saying by ESPN. "We will have to keep fighting. Whatever happens we are willing to fight."
Pinto took charge of Costa Rica in 2011.