Guillermo Mendizábal Sánchez (born 8 October 1954) is a Mexican former footballer and manager.
He debuted with Cruz Azul in the 1974–75 season, and helped the team win the 1978–79 and 1979-80 league titles.
During his footballer career he played for Cruz Azul, UAG, Rayo Vallecano, and Club Deportivo Guadalajara.
[3] After hanging his boots, he began his managing career in 1995, at León AC where he only last the 1995–96 season.
At the time he was playing for Cruz Azul his teammates would call him "Mendi" (to shorten his last name) and the "M" was changed to a "W" and since then his being known as "Wendy".