Formula One leader Sebastian Vettel posted the fastest time in the second practice for the Italian Grand Prix, more than six-tenths of a second faster than teammate Mark Webber for a Red Bull 1-2 on Friday.
Vettel, who won at Monza in 2011, was 0.623 seconds faster than Webber and looked in complete control from the start of the afternoon session. It is a telling sign for his rivals ahead of Sunday's race.
"It was a good day, that's for sure, but we've got our feet on the ground," Vettel said. "It's still only a Friday. I don't know, maybe the others had some problems. I didn't have any issues with the car, it felt pretty comfortable.
The three-time defending champion leads second-placed Fernando Alonso by 46 points in the standings.
Red Bull has not achieved the best results at Monza, and Vettel's win two years ago is its only podium position since 2005. However, the German looked in impressive form and could be on course for a fourth victory of 2013.
Kimi Raikkonen was third in perfect conditions at Monza, 0.663 seconds behind Vettel, with the same time as Lotus teammate Romain Grosjean.
Alonso, Lewis Hamilton, Nico Rosberg, Felipe Massa, Jenson Button and Sergio Perez completed the top 10 with little more than half a second between Perez, in 10th, and Webber.
Hamilton, who won at Monza last year, was fastest in the morning session, 0.035 seconds better than Alonso, with Vettel fourth quickest, 0.188 seconds slower.
Rosberg was third, 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.
Ferrari was fined $13,000 after Massa crossed the white line at the end of the pit lane after the red light had come on to indicate the end of the first practice session.
An investigation by stewards determined the Brazilian "had made every attempt to stop" and "no sporting advantage was gained" but added "the team made an error in releasing the car with insufficient time remaining in the session."