The controversial seventh-minute strike, which came when the former Genoa player touched in Houssine Kharja's effort, powered Inter up to second spot and just two points behind leaders AC Milan ahead of their visit to Chievo on Sunday.
Holders Inter host Bayern Munich in a Champions League last-16 first leg on Wednesday, a repeat of last season's final, and coach Leonardo used the Cagliari game to give Goran Pandev a rare start.
The Macedonia striker is set to fill in against the Germans for the ineligible Giampaolo Pazzini, partnering Samuel Eto'o who was taken off in an insipid second half on Saturday to spare his legs.
In Saturday's other Serie A match, seventh-placed Palermo's hopes of a Champions League spot took a blow when Daniele Paponi's header in stoppage-time gave mid-table Bologna a 1-0 home win.
