The Central Americans booked their place in the quarter-finals of the tournament following a penalty shootout victory on Saturday.
"Last night, I dreamt, this, it seems untrue," BBC Sport quotes him as saying.
"I was relaxed because I dreamed it. I dreamed it but I didn't tell anyone. I felt very confident.
"This is for my family. It's for the colleagues who got injured before coming here. They're not with us, but they gave us a hand on the pitch."
Costa Rica will face the Netherlands in their quarter-final tie on Saturday.