Title contender Lazio beats Cagliari 2-1 with late goals
Giovanni Simeone put Cagliari ahead with a volley seven minutes in.
The Roman club won its only two Serie A titles in 1974 and 2000 and was not expected to be a contender this season.
Cagliari remained fifth after having a 13-match unbeaten streak ended.
Opposing fans clashed outside the stadium before kickoff.
Lazio, which was recently eliminated from the Europa League, meets Juventus in the Italian Super Cup on Sunday in Saudi Arabia.