On 21 June 2007, Borriello was sold to Genoa in a co-ownership deal with Milan, for €1.8 million. Borriello helped newly promoted Genoa get their first win of the season, scoring his first hat-trick at the expense of Udinese. The game ended 3–2, with the striker scoring from the penalty spot in the 76th minute. Incidentally, in the return fixture on 24 February 2008 in Udine, Borriello hit another hat-trick in a 5–3 away win, reaching 15 league goals in the process. He finished the season with 19, making him the third-highest goalscorer in the league behind Juventus pair Alessandro Del Piero and David Trezeguet.