Peru slipped to a 3-1 friendly defeat at Chile in the first leg of their Copa del Pacifico duel on Wednesday.
Esteban Paredes gave home side Chile a fifth-minute lead in Arica when he raced down the left before drilling a low shot inside the far post.
The lead lasted 16 minutes, with Peru equalising when defender John Galliquio sidefooted home a low cross delivered from the left by Yoshimar Yotun, but Chile were ahead again before half-time.
Their second goal came in the 43rd minute when goalkeeper Salomon Libman made a hash of an attempted punch clear of his lines, and Enzo Andia was on hand to bundle home from close range.
Mena charged clear of the Peru defence in the 86th minute and lifted a left-footed shot over Libman to seal the victory.
The second leg of the traditional international friendly head-to-head between the nations takes place in Tacna on 11 April.
The matches serve as preparation for the next round of World Cup qualifiers in June, when Chile travel to Bolivia and Peru host Colombia in Lima.