The Fiorentina forward, who has been named to Italy's squad for the nation's November friendlies, has been stellar since returning from a long-term knee injury.
Strikes from the Italy international in the 11th and 17th minute saw the Viola race to a two-goal lead and, though Manolo Gabbadiani pulled one back late on, the hosts held on to gain all three points.
Rossi had been out of action for more than a year with a knee injury but is making his mark in Serie A this season after signing for Vincenzo Montella's side in January from Villarreal. And after being named in Cesare Prandelli's Azzurri squad to face Germany and Nigeria, he stressed that his form and fitness are continuing to improve.
"I feel good. Today I played 90 minutes," the 26-year-old told Mediaset Premium. "I can give more, but in every game I always feel better.
"I hope to be a fundamental part of the Italy team that will participate in the World Cup. Every game I try to do my best to get results. This [Italy call-up] is one more incentive which gives me satisfaction."
Fiorentina sits fifth in Serie A - eight points behind league leader Roma - and trails Inter by one point.