 These performances earned Rocchi a €1.5 million move to Lazio for the 2004–05 season, in another co-ownership deal.Rocchi's first goal of the championship for Lazio came on 22 September 2004 against Brescia at the Stadio Mario Rigamonti in a 2–0 win.His finest individual performance of the season was a hattrick against Lecce, and Rocchi ended a successful debut season with 13 goals in 35 league appearances.