Orbelin Pineda's penalty just before halftime gave Mexico a 1-0 win over Costa Rica in San Jose on Sunday in the final round of CONCACAF World Cup qualifiers.
Hosts Costa Rica had their chances to equalise in the second half, particularly in stoppage time, but Mexico's resolute defence stood firm.
Mexico lead the eight-team table with six points from two games, two points ahead of Panama, who drew 0-0 with Costa Rica on Thurday.
Mexico meet Panama on Wednesday while Costa Rica play Jamaica.
(Reporting by Rory Carroll in Los Angeles; Editing by Peter Rutherford)