An Argentine footballer from Buenos Aires, Mariano Gonzalo Andujar began his professional career with Club Atletico Huracan in 2001. Even though the club was relegated after two years, Andujar remained with the team, and in 2005, Andujar was loaned to Italian club, Palermo. Andujar was supposed to be the third goalkeeper after Nicola Santoni and Matteo Guardalben, but both players were sold in the January transfer window and Federico Agliardi came in, instead Andujar was used as goalkeeper more often and he appeared in 11 league matches, as well as three Coppa Italia matches and 7 UEFA Cup matches.
The football goalkeeper returned to Argentina in 2006, where he joined up Estudiantes, and made 16 appearances in the Apertura 2006 campaign, where he conceded on 9 goals. The season reflected one of the tightest defense set up by Estudiantes, with only 13 goals conceded in 20 games.
Andujar was the goalkeeper in the playoff between Estudiantes and Boca Juniors for the Apertura 2006 title, which Estudiantes won 2-1, claiming their first title win in 23 years.