Saturday's FP3 was made more intriguing, and significant, due to the ATA or alternative tyre allocation in place for this weekend.
Teams received two fewer sets of tyres from Pirelli and will also have to use all three compounds throughout the three qualifying stages.
That meant that rather than just completing soft-tyre qualifying simulations, they also had to consider bringing the hard and medium tyres into play to prepare for Q1 and Q2 respectively.
That split was most obvious between the top teams, who focused almost exclusively on soft-tyre pace for Q3 versus midfield teams less confident about their ability to survive Q1 and therefore paying extra attention to harder tyre running.
McLaren man Lando Norris led the early soft tyre running ahead of Red Bull's Sergio Perez and Ferrari's Sainz.
Runaway championship leader Max Verstappen soon demolished that time by dipping below the 1m22 barrier with a first effort of 1m21.838s, with Perez following in second ahead of Mercedes' Lewis Hamilton. After 15 minutes Verstappen then lowered his own benchmark to a 1m21.687s.
Those times remained unchanged until right before the halfway mark when Kevin Magnussen grabbed third in the medium-shod Haas in between Perez and Hamilton, a sign of Monza's track getting ever faster.
Source: Autosport