[1] Ganzabal made his Grand Slam debut in the 1981 French Open and managed to reach the third round, beating former finalist Manuel Orantes and American Steve Krulevitz.

[2] In 1982 he was runner-up in the Buenos Aires Grand Prix tournament and made quarter-finals at Venice, Boston and Quito.

[2] At these tournaments he secured two wins over top 20 player Tomáš Šmíd and also defeated world number 11 Henrik Sundström.

In 1982 he played a doubles rubber with Guillermo Vilas, which they lost to the French pairing of Gilles Moretton and Yannick Noah.

He other two matches were dead rubbers and he lost both, against Michael Westphal of West Germany and American player Gene Mayer.