Lewis Hamilton posted the fastest time in Friday's first practice session for the Italian Grand Prix, with championship leader Sebastian Vettel fourth quickest.
Hamilton, who won at Monza last year, set a time of 1 minute, 25. 565 seconds, 0.035 seconds faster than Ferrari driver Fernando Alonso.
Nico Rosberg was 0.139 seconds slower than his Mercedes teammate. Hamilton has qualified in pole position in the past four races, while his team has done so in eight of the past nine.
Vettel, who won at Monza in 2011, was 0.188 seconds behind Hamilton. The three-time defending champion leads Alonso by 46 points in the standings and is 58 points ahead of Hamilton.
The field was tightly packed at a high-speed Monza track, with less than half a second separating Hamilton from Jenson Button in seventh. There was less than a second gap between the top 14, with Ferrari driver Felipe Massa only 0.884 seconds slower than Hamilton.
Button teammate Sergio Perez was sixth, which is a positive sign for McLaren as it searches for its first podium of the season to help celebrate the team's 50th anniversary this weekend.
