Briton Lewis Hamilton finished nearly a second ahead of McLaren team-mate Jenson Button to top the times in Friday morning’s opening free practice ahead of the Italian Grand Prix.
The 26-year-old Hamilton, the 2008 world champion, clocked 1min 23.865secs at the Autodromo Nazionale Monza with fellow Englishman Button, 31, second in 1:24.786.
Defending champion and current series leader Sebastian Vettel of Germany was third in his Red Bull with Australian team-mate Mark Webber, 35, in fourth.
Another German, Adrian Sutil of Force India — powered by the same Mercedes engines as the McLaren pair — was fifth ahead of Russian Vitaly Petrov in the leading Renault.
Two-time champion Fernando Alonso of Spain was seventh fastest for Ferrari ahead of Brazilian team-mate Felipe Massa, with Mexican Sergio Perez of Williams and another Spaniard, Jaime Alguersuari of Toro Rosso, making up the top ten.
Seven-time champion and former Ferrari legend German Michael Schumacher, 42, was 11th for Mercedes, one place ahead of his compatriot Nico Hulkenberg in the second Force India.
Brazilian Bruno Senna, in his second outing for Renault after ousting German Nick Heidfeld from his seat, was 16th fastest on a warm, dry and mostly sunny morning.