Mercedes enjoyed a one-second advantage over the field as Valtteri Bottas set the pace in Practice 1 at the United States Grand Prix.
Ahead of this weekend, a lot of talk had centred around the bumps at Circuit of the Americas after the issues faced by MotoGP a few weeks ago.
And despite efforts by the track owners to reduce their harshness, cars were seen bouncing particularly violently through the Esses in the first sector.
Several drivers also seemed to be caught out, including Charles Leclerc who went off at Turn 6 before continuing in his Ferrari.
The early moments of the session saw a red flag caused by Fernando Alonso, as his Alpine ground to a halt at Turn 12 with a mechanical problem.
Not a good start to the session for Fernando Alonso, his Alpine comes to a halt
— Formula 1 (@F1) October 22, 2021
He hitches a ride back to the garage 🛵#USGP 🇺🇸 #F1 pic.twitter.com/Z1SYsa4f1r
Happily for the Spaniard, his car was recovered and he was able to get back out on track albeit only finishing 15th fastest.
At the front, Mercedes laid down an early benchmark with Bottas posting a 1m34.874s, just 0.045s clear of teammate Lewis Hamilton.
The big news during the session though was that the Finn would be taking a third grid penalty in four races for new engine components, although this time it is only five places.
Max Verstappen would be the only driver within a second of the Black Arrows but only just in the Red Bull.
Ferrari began well in fourth and fifth for Leclerc and Carlos Sainz respectively, with Pierre Gasly also carrying his strong pace from Turkey to Austin in sixth.
Sergio Perez would have been third had his best time not been deleted for track limits, instead, he was only seventh ahead of Lando Norris' McLaren.
Completing the top 10 was the two Alfa Romeos with Antonio Giovinazzi 0.002s quicker than 2018 US GP winner Kimi Raikkonen.
George Russell will start from the back of the grid for a fresh power unit in his Williams, but the Brit showed strong early pace in 11th for Williams.
The team can confirm that George has taken new power unit elements this weekend and therefore will incur a grid penalty.
— Williams Racing (@WilliamsRacing) October 22, 2021
Still plenty to play for this weekend, GR 👊 pic.twitter.com/9IaV21rpRO
Esteban Ocon was 12th, ahead of the Aston Martin pair of Lance Stroll and Sebastian Vettel. The German was the third confirmed driver with an engine penalty, joining Russell at the back of the grid.
Daniel Ricciardo was 16th in front of Nicholas Latifi and Yuki Tsunoda. In P19 was Mick Schumacher, who made slight contact with Perez at Turn 12 late on after a misunderstanding.
Finally, Nikita Mazepin had a high-speed off at the penultimate corner in his Haas, and would end the session some seven seconds off the pace in P20.
Full results from Practice 1 can be seen below:
