Max Verstappen topped opening practice at the Italian Grand Prix ahead of Carlos Sainz in a closely contested session between Red Bull Racing and Ferrari.
Verstappen undertook three stints on the hard tire on his way to a fastest time of 1m22.657s, pipping Sainz by just 0.045s, the Ferrari driver on a four-stint hard-tire plan.
Sergio Perez and Charles Leclerc followed, the pair respectively 0.177s and 0.309s off the pace, with George Russell completing a top five all exclusively on hards.
Sainz, Leclerc and Russell were all competing with brand-new power units, the last of their allocation for the season.
Pirelli’s alternative tire allocation dictated running, with most drivers completing the session with a single compound, though fears running would be curtailed to preserve rubber proved unfounded.
The rules in force for this weekend are the same first used in Hungary and see each driver handed two fewer sets of tires for the weekend comprising a greater proportion of hards and mediums than soft.
Fernando Alonso was sixth on the medium tire at 0.557s off the pace, although his fastest lap was boosted by a slipstream from stand-in teammate Felipe Drugovich.
Lando Norris followed in seventh for McLaren as the only driver to use two compounds, setting a pair of installation laps on the medium tire before completing the session on softs.
Lewis Hamilton was out of position in eighth on the hard tire at the head of a midfield that mostly utilized softs.
Yuki Tsunoda — also using the last of his allocated brand-new power units — was ninth for AlphaTauri ahead of Alex Albon, who had the session’s only meaningful off with a snap of oversteer that sent him through the stones at Ascari. Oscar Piastri followed in 11th ahead of American rookie Logan Sargeant.
Daniel Ricciardo’s injury substitute, Liam Lawson, put his AlphaTauri 13th, his car also equipped with a new motor. He finished ahead of Pierre Gasly, who complained of bouncing down the straights on his way to 14th place.
Valtteri Bottas was the lead Alfa Romeo driver on a difficult day for the Italian-branded Swiss team. Despite the Finn using a new engine, both he and teammate Zhou Guanyu found themselves stuck in pit lane at the start of the session due to an apparent clutch issue, with both cars entering anti-stall when the drivers lifted the clutch.
When they eventually got back on track after around 20 minutes in their garages, both reported problems with rear grip, forcing both back to pit lane for further checks. Bottas and Zhou completed just 16 laps apiece, with the former in 15th and the latter last in the order.
Nico Hulkenberg completed the session on mediums on his way to 16th ahead of Esteban Ocon, Aston Martin reserve driver Felipe Drugovich and Kevin Magnussen