Hamilton, whose future is still undecided, went fastest in the third and final free practice session, beating current Championship leader Fernando Alonso by just one thousand of a second as prospects for a close fight for pole position continued to grow.
Force India driver Paul di Resta, who has been given a five place grid drop, surprised many by completing the top three. Brazilian Ferrari driver Felipe Massa came in fourth ahead of McLaren's Jenson Button, who is aiming to win at Monza after winning last weekend's Belgian Grand Prix.
Mercedes driver Nico Rosberg, who was the first of the frontrunners to switch to the mediums, ended the session in sixth.
Mexican Sauber driver Sergio Perez was seventh quickest in the first of the Saubers ahead of Lotus' Kimi Raikkonen and German Force India driver Nico Hülkenberg. Venezuelan Williams driver Pastor Maldonado completed the top ten, keeping both Red Bulls, who have been struggling all weekend, out of the top ten.
