Aguado was part of the Zaragoza side that beat Arsenal in the final of the 1994–95 UEFA Cup Winners' Cup. From 1997 to 1999 he scored a total of nine league goals, including a brace in a 2–2 home draw against SD Compostela on 28 September 1997. However, during his 13-year career at the Aragonese, he also amassed a poor disciplinary record, collecting in the league alone 109 yellow cards and being sent off 18 times, the latter being an all-time worst in the competition.