Hamilton, who has won five times at the Circuit of the Americas, had led the way at the top of the timesheets for much of the first practice session, but it was his Mercedes teammate Bottas who ended up with the fastest time. 

Bottas edged out Hamilton by just 0.045s as the Mercedes pair were the only two drivers to dip into the 1m34s in a dominant FP1 display, with current championship leader Max Verstappen nearly a full second adrift in his Red Bull. 

During the opening hour of the first track action in the United States in two years it was confirmed that Bottas will serve a five-place grid penalty this weekend after switching onto his sixth internal combustion engine, with Mercedes admitting it is trying to “contain” a reliability issue with its 2021 engine. 

Fellow Mercedes-powered cars of George Russell and Sebastian Vettel will also take grid penalties in Austin after Williams and Aston Martin decided to fit new engines on their respective cars. 

The Ferraris of Charles Leclerc and Carlos Sainz were a second and a half off the pace of the dominant Mercedes as they finished fourth and fifth, ahead of AlphaTauri’s Pierre Gasly

Sergio Perez was nearly two seconds down in the second Red Bull in seventh as he bumped into Mick Schumacher’s Haas under braking at Turn 12 in the closing minutes of FP1. 

Lando Norris was eighth fastest for McLaren, while the Alfa Romeo duo of Antonio Giovinazzi and Kimi Raikkonen completed the rest of the top 10. 

The session was interrupted by a brief early red flag when Fernando Alonso stopped on track during his installation lap, with fluid seen leaking out of his Alpine car. 

Although it looked like Alonso’s session might be over, the Spaniard was able to get back out following the precautionary stoppage to log 12 laps on his way to 15th. 

The Haas cars of Schumacher and Nikita Mazepin rounded out the bottom of the timesheets at their first home event in two years. 

Full opening practice results for the 2021 F1 United States Grand Prix.