Lewis Hamilton led teammate Nico Rosberg in opening practice for the Italian Grand Prix as Mercedes was in a league apart as the action kicked off at Monza.
Hamilton's best of 1:24.670 put him nearly half a second ahead of Rosberg, but over 1.5 seconds in front of the closes non-Mercedes car.
A late improvement from Sebastian Vettel elevated him to third place in the Ferrari, before the German spun at the first chicane with seven minutes to go.
Nico Hulkenberg was fourth fastest ahead of teammate Sergio Perez, as Force India began the weekend in strong fashion. They were two seconds off Hamilton's pace, however.
Pastor Maldonado completed the top 10 in the Lotus.
McLaren had a short session as both Jenson Button and Fernando Alonso stopped in the pits early for a scheduled engine change. They both finished over three seconds off the pace.
It took nearly 13 minutes for a driver to appear on the timesheets, when Max Verstappen completed the first timed lap as Toro Rosso teammate Carlos Sainz was forced to return to the pits after complaining repeatedly of problems when changing gears.
Hamilton took first place 19 minutes into the session with the first lap in the 1:27s, over half a second clear of the opposition at the time.
Maldonado jumped to P1 briefly before Hamilton completed another flyer - a 1:26.305 - to regain the top stop, followed by teammate Rosberg, less than three tenths behind.
But the reigning world champion opened a gap of nearly a full second on his fifth lap, setting a new benchmark of 1:25.653.
After his early problems, things would go worse for Sainz after the Spaniard lost control of his car at Parabolica, ending up in the gravel and forcing the session to be red-flagged right before the half-hour mark.
The Toro Rosso driver ended the session with just eight laps and near the bottom of the times.
The action resumed after over 10 minutes of silence, but it took until the one-hour mark for a change at the top of the times, when Rosberg posted a quickest time of 1:25.423 to outpace Hamilton by nearly three tenths of a second.
Hamilton reacted right away and retook the top spot with a 1:25.152.
Rosberg improved seconds later, but fell just 0.011 seconds short of Hamilton's best.
Hamilton went even faster, however, becoming the first man to dip into the 1:24s with a 1:24.670, a time that would remain unbeaten.
|4||Nico Hulkenberg||Force India||1'26.612||1.942||19|
|5||Sergio Perez||Force India||1'26.730||2.060||29|
|7||Daniel Ricciardo||Red Bull||1'26.922||2.252||27|
|12||Daniil Kvyat||Red Bull||1'27.275||2.605||29|
|14||Max Verstappen||Toro Rosso||1'27.591||2.921||27|
|16||Carlos Sainz||Toro Rosso||1'27.907||3.237||8|