Sebastian Vettel topped the times ahead of Mark Webber as Red Bull dominated Friday afternoon's practice session ahead of this weekend's Italian Grand Prix.
The defending triple world champion was fastest throughout and clocked a best lap time of one minute and 24.453 seconds at Monza, leaving the German six-tenths of a second clear of the field.
Australian Webber was second ahead of Finn Kimi Raikkonen and his Lotus team-mate, Frenchman Romain Grosjean, with Spaniard Fernando Alonso fifth for Ferrari and Briton Lewis Hamilton sixth for Mercedes.
Hamilton's Mercedes team-mate German Nico Rosberg was seventh ahead of Brazilian Felipe Massa in the second Ferrari and the two improved McLarens of Briton Jenson Button and Mexican Sergio Perez.
Vettel holds a clear lead in the drivers' standings with 197 points ahead of Alonso on 151 and Hamilton on 139.
