Stefanio Eranio scored the decisive goal with a powerful header in the 60th minute following a fine run and cross from Zvonimir Boban.
Sampdoria remain second on 36 points following a 1-0 home win over Torino thanks to a stunning volleyed goal from Ruud Gullit in the 13th minute. It took Gullit's tally for the season to 14.
Fourth-placed Parma lost ground on the leading group after their match with Reggiana was abandoned at half-time when the referee, Pierluigi Pairetto, pulled a leg muscle. No replacement official was available.
In the Netherlands, Ajax came from behind to beat the relegation candidates, SC Cambuur Leeuwarden, 3-2. The Amsterdam club were trailing 2-0 at half-time, but Peter Van Vossen secured victory 10 minutes from time. With second-placed Feyenoord dropping a point in a 1-1 draw at Go Ahead Eagles, Ajax extended their lead at the top of the league.
In France, the Brazilian striker, Anderson da Silva, scored twice to help Marseille to a hard-fought 3-2 home win over lowly Lille.
Marseille looked on their way to a comfortable victory but the Lille striker, Eric Assadourian, scored within a minute of Anderson's second goal and then made it 2-2 in the 52nd minute.
Rudi Voller enabled Marseille to pick up two precious points by scoring the winner in the 68th minute.
In Germany, Christian Nerlinger and the Colombian, Adolfo Valencia, scored in the second half to restore Bayern Munich's lead in the German league with a 2-0 home victory over the defending champions, Werder Bremen.