Costa Rica win despite missing penalty
Andy Furtado, scorer of two goals in a 2-0 win over Honduras in February, won the penalty in the 26th minute and took the kick himself only to see his effort saved by Miguel Montes.
Playmaker Walter Centeno, 34, finally broke through for the hosts when he headed in Carlos Hernandez's cross in the 69th minute of his 127th international.
El Salvador, missing playmaker Eliseo Quintanilla through suspension, had their best effort just before the penalty when Julio Martinez headed against the post.
The win put Costa Rica second in the final stage of the CONCACAF qualifiers, which is played as a six-team mini-league.
The Ticos have six points from three games, one behind leaders the United States.
El Salvador, whose last World Cup apperance was in 1982, are fifth with two points.