 After a number of seasons in the youths and reserves at the club, including the Auxerre reserves' Division 3 championship-winning season in 1985–86, Mazzolini was promoted to the first team at the start of the 1987–88 season.He made his Division 1 début for the club on 20 September 1987, in the 0–1 defeat away to RCF Paris.His first goal for Auxerre came in the 61st minute of the 2–0 victory over Sporting Toulon Var on 16 September 1989.