Blackburn out-jumped defenders to score on a header off a post. Perez scored off a pass from Alberto Quintero.
Panama (3-1) leads Group C of the North and Central American and Caribbean semifinals with nine points, followed by Honduras and Canada (both 2-1-1) with seven points each, with the Central Americans ahead of goal difference. Cuba (0-4) is last.
The top two nations advance to next year's regional finals, which will produce three qualifiers for the 2014 tournament in Brazil.