 He spent two seasons in Serie B with the rosanero, before the club made a glorious return to Serie A in 2004–05.He continued his excellent form in the top flight, and after one season was rewarded with a move to capital club Lazio, signed a 5-year contract as free agent.Mutarelli's first season with the Biancocelesti was a good one, and he capped off a quality first season in Rome, with a goal in the historic 3–0 Derby win over inter-city rivals Roma.