
McLaren rivals Lewis Hamilton and world champion Felipe Alonso were third and fourth respectively at Monza.
Finnish driver Raikkonen clocked 1 minute 22.446 seconds to edge his Brazilian team-mate by 0.144 seconds.
Britain's Hamilton, the overall leader, posted 1:22.618 with Spain's Alonso on 1:22.840.
The German Nico Rosberg in a Williams was fifth in 1:23.472, while Britain's Jenson Button in a Honda was sixth in 1:23.668.
Germany's Nick Heidfeld in a BMW-Sauber, who is fifth overall, was ninth, one place behind teammate Robert Kubica of Poland.
Hamilton leads the drivers' standings on 84 points, with Alonso on 79, Massa on 69 and Raikkonen on 68.
DPA