[1] Coach Luis Aragonés handed him his top flight debut in a 3–0 home win over Osasuna at the Vicente Calderón Stadium on 9 September 1984.
He was somewhat more prominent the following season as Mérida claimed the Segunda División title at the first attempt, earning Mendiondo the fourth La Liga promotion of his career.
[4] The same year, Mendiondo played all four matches for the under-21 side at the Toulon Tournament, in which Spain placed third after a third-place play-off win over Cameroon.
Fenerbahçe reached the final of the 2008–09 Turkish Cup in Aragonés and Mendiondo's solo season at the club,[2] ultimately losing to Beşiktaş.
Ahead of the 2015–16 season, Mendiondo took charge of Israeli Premier League team Hapoel Tel Aviv,[9] replacing Eli Cohen.