AC Milan needed a lucky own goal by defender Mirko Conte to overcome Sampdoria 1-0 in the first leg of the Italian Cup second round on Wednesday.
Playing without regular strikers Filippo Inzaghi and Andriy Shevchenko, Milan failed to capitalise on long periods of possession in both halves.
With 11 minutes left, Sampdoria defender Maurizio Domizzi cut out a low cross by visiting midfielder Cristian Brocchi, but Conte was in the way and the ball bounced off him into the net.
In an earlier match, goals by strikers Simone Inzaghi and Roberto Muzzi gave Lazio a 2-0 win over Modena.
The visitors took the lead three minutes before halftime, when a poor clearance gifted Inzaghi possession deep in Modena's half, allowing him to dribble into the area and fire low past keeper Adriano Zancope.
Ex-Udinese striker Muzzi added the second after 65 minutes, taking advantage of an Inzaghi nod-on to burst between two defenders and drive the ball into the top of the net.
Modena came closest to scoring nine minutes from time when midfielder Riccardo Allegretti whipped a dangerous free kick into the area, but Lazio keeper Matteo Sereni tipped it round the post.
In Wednesday's other Cup fixtures, Udinese beat Bologna 1-0, while Parma defeated Serie B side Venezia 2-0.