Ferrari looked the class of the field in the sole practice session for the US Grand Prix on Friday, putting both of their cars at the top of the timesheets with just a couple of hundredths of a second between them.
Max Verstappen's early push lap put him third in the session, but his team-mate Sergio Perez's struggles continued, over a second off the pace and all the way down in 16th.
Lewis Hamilton and George Russell both spun at high speed during the session, but were saved from any costly contact with the wall by the large run-off areas at the track.
The Sauber of Zhou Guanyu exited the session early, coming into the pits and being taken apart after the Chinese driver complained of a loss of power while out on track.
Yes, sprint qualifying is due to take place later on Friday, with the championship protagonists battling it out for pole position. The session is due to start at 10:30pm BST.