Charles Leclerc completed a Ferrari clean sweep of Friday practice for the United States Grand Prix in an FP2 session devoted to a Pirelli 2023 prototype tyre test.
The Monégasque set the benchmark with a one minute 36.810, but having stood aside for Robert Shwartzman in the first session, was allowed to use the opening 30 minutes to complete a weekend-specific programme.
Therefore, the times for Leclerc, who set his best lap on a set of mediums, Valtteri Bottas and Daniel Ricciardo were all skewed compared to the rest of the field, whilst Kevin Magnussen and Nicholas Latifi passed on the opportunity to use the exemption.
Pirelli gave set parameters for the test, with two prototype compounds for next season on offer. The rubber was unmarked with teams given no prior indication as to which compound was which.
All teams were limited to either three-lap runs on 20kg of fuel or eight-lap stints on 100kg of fuel, with tyre blankets heating the tyres to 50 degrees Celsius, rather than the 70 degrees currently permitted by the regulations.
Teams were not allowed to change set-ups between runs, hence the exemptions for those drivers who missed out on FP1 running.
Running was almost constant and resembled a pre-season test, although there were some moments that piqued interest.
Lewis Hamilton was called out by Fernando Alonso for "unbelievable" driving, the Alpine driver grovelling over team radio: "Hamilton has no mirrors today."
The Briton almost lost control of his Mercedes when running wide at turn 19 later in the session, whilst DRS issues will ensure the team has work to do ahead of FP3.
Lando Norris was spared his blushes after drifting his McLaren through the pit-lane entry corner on the inside of the final turn, just managing to avoid the wall.
Off-track, Brad Pitt made a visit to Red Bull to talk to Christian Horner and Max Verstappen as he prepares to star in the Lewis Hamilton-affiliated F1-themed movie.
Those taking part in the test completed 26 laps each, including in and out laps, with Leclerc, Bottas and Ricciardo each reaching and surpassing 30 laps.
Unsurprisingly, the trio completed the top three, with Carlos Sainz the first of those to have tested the prototypes throughout.
The Spaniard was 1.4secs slower than the lead Ferrari's best time on mediums, giving an indication of the difference in tyre compounds between this year and next.
For what it is worth, Mick Schumacher was fifth fastest ahead of Norris, with Verstappen, Hamilton, Pierre Gasly and Sergio Perez rounding out the top 10.
The data gathered during the session, combined with the learning from a similar session in Mexico, will assist Pirelli in confirming its compound constructions for 2023 as F1's tyres evolve.
The tests would usually be completed on individual, private Pirelli test days, but due to the intensity of the calendar this season, there was no option but to use two free practice sessions to ensure the relevant running was undertaken.