Umana featured in two of the side's three Group D games as Costa Rica finished top thanks to seven points from a possible nine.
Next up are Greece in the knockout stages on Sunday as Costa Rica seek to make it into the quarter-finals of a World Cup for the first time.
Costa Rica's previous best effort came at Italia '90 when they were beaten by Czechoslovakia in the last 16, but Umana says his team-mates are focused on extending their time in Brazil.
"It is true that it is one of the strange things being away from our country, family and loved ones," he told Al Dia.
"But right now we are focused on reaching as far as possible, hopefully to July 13 when the World Cup ends.
"This team is mentally prepared to make history and we want to continue to do so in the World Cup. We are all united in a common goal."
Victory for Costa Rica would see them take on the Netherlands or Mexico in the quarter-finals.
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