Andrew Benson
BBC F1 correspondent in Austin

Image source, Getty Images

Ferrari's Charles Leclerc led Mercedes' Kimi Antonelli in Friday practice at the United States Grand Prix.

Leclerc, who topped both sessions, was 0.042 seconds ahead of the Italian, who has a mathematical chance of tying up his first world title this weekend.

Red Bull's Max Verstappen was third fastest, 0.189secs back, ahead of Ferrari's Lewis Hamilton, although the seven-time champion was 0.615secs off the pace.

Mercedes driver George Russell was fifth ahead of Racing Bulls' Liam Lawson.

McLaren's Lando Norris, whose team have introduced the first of three consecutive planned upgrades this weekend, was seventh fastest, although the world champion did not set a time on his qualifying simulation run on soft tyres after making a mistake at Turn 16.

McLaren's Oscar Piastri was eighth quickest, ahead of Red Bull's Isack Hadjar and Haas driver Oliver Bearman.

Antonelli will win the championship in Austin only if he wins the race and Russell finishes below eighth and Hamilton below fourth.

Read the full report here

The upgraded Ferrari has lifted Charles Leclerc to the top of the pile in both practice sessions in Austin on Friday, but can the Monegasque driver stay there when it counts on Saturday?

Kimi Antonelli was only 0.042 seconds behind Leclerc, so are Mercedes finally unlocking the potential of their big updated? The Italian has his first shot at claiming the world championship this weekend, but he needs a flawless qualifying and grand prix, plus George Russell and Lewis Hamilton to slip up, to be crowned the winner with races to spare.

Down at the bottom of the field, Williams are having a nightmare start to their US Grand Prix, with Alex Alex and Carlos Sainz both struggling with the car in the second hour after an opening session of development running.

We'll be back up and running for third practice build-up from 18:15 BST tomorrow.

The fight for pole position gets under way at 22:00.

See you on Saturday!

11. Gabriel Bortoleto (Audi)

12. Pierre Gasly (Alpine)

13. Arvid Lindblad (Racing Bulls)

14. Esteban Ocon (Haas)

15. Franco Colapinto (Alpine)

16. Fernando Alonso (Aston Martin)

17. Lance Stroll (Aston Martin)

18. Nico Hulkenberg (Audi)

19. Valtteri Bottas (Cadillac)

20. Carlos Sainz (Williams)

21. Sergio Perez (Cadillac)

22. Alex Albon (Williams)

1. Charles Leclerc (Ferrari) - 1:35.291

2 Kimi Antonelli (Mercedes) +0.042

3. Max Verstappen (Red Bull) +0.189

4. Lewis Hamilton (Ferrari) +0.615

5. George Russell (Mercedes) +0.744

6. Liam Lawson (Racing Bulls) +1.040

7. Lando Norris (McLaren) +1.082

8. Oscar Piastri (McLaren) +1.096

9. Isack Hadjar (Red Bull) +1.120

10. Oliver Bearman (Haas) +1.245

Ferrari might have one driver setting the pace at Cota, but the other is "struggling to stay on track". Lewis Hamilton is 0.615 second off his team-mate Charles Leclerc and adds he is "dropping off massively" during his long run. The seven-time world champion comes in and takes on a set of hard tyres for the last few minutes of the session.

Lando Norris gets a phone call from his race engineer Will Joseph, who says Ferrari's Charles Leclerc has similar limitations to the McLaren driver on his soft tyres.

Sky Sports then picks up with McLaren CEO Zak Brown, who explains "this could be an interesting race when it comes to track limits", adding "everyone is struggling and sliding around".

The two Aston Martins of Lance Stroll and Fernando Alonso have joined world champion Lando Norris on the hard compound for the final 10 minutes of this session. Spaniard Alonso and Canadian Stroll are in P16 and P17, while McLaren's Norris is up in the top 10 in seventh.

Kimi Antonelli has been put on the medium tyre for these latest laps, as Oscar Piastri runs wide on the soft rubber.

Liam Lawson still doesn't know if he'll be driving for Racing Bulls next year, but the New Zealander has done everything he can to claim a seat on the grid next year. He scored double points in Singapore last time out in both the sprint and main race and he's sixth on the timehseets in FP2 so far. And he did a proper gig in Austin last night. Man of many talents.

Esteban Ocon, meanwhile, has reached Turn 17 and has the Ferrari of Charles Leclerc ahead of him. The Haas driver is not impressed with the Monegasque man's positioning on track, calling in to ask his engineer: "What is he doing?"

Image source, Getty Images

Esteban Ocon is leaving Haas at the end of the season, so who is replacing the Frenchman at the American-based team?

Enter Brazilian Rafael Camara, who will be making his Formula 1 debut with Haas next year.

The 21-year-old is leading the Formula 2 championship by seven points and beat the likes of reigning F2 champion Leonardo Fornaroli and Haas reserve drivers Jack Doohan and Ryo Hirakawa to the seat.

Haas team principal Ayao Komatsu said Camara, who is a member of the Ferrari driver academy, had been the quickest driver at the tests in Portugal this summer.

"In Portimao, he was just simply outstanding. We really wanted to go for someone who had that natural speed," Komatsu said.

Charles Leclerc and Kimi Antonelli are leading the field in second practice, with Max Verstappen the closest challenger in third place.

Behind the top three, the other Ferrari of Lewis Hamilton is six tenths off his team-mate Leclerc in fourth, with George Russell off the pace of his Mercedes team-mate Antonelli by seven tenths in fifth.

Fernando Alonso is full of praise for George Russell's performance in this session.

Or maybe not.

"Bravo Russell," says the two-time world champion sarcastically, as the Mercedes driver blocks the path of the Aston Martin during his run on the soft tyre. "That was painful," replies Alonso's engineer.

Image source, Reuters

Rebecca Clancy
F1 journalist on BBC Radio 5 Sports Extra in Austin

Max Verstappen is one of those drivers who don't need the car to be perfect to get everything out of it. It just needs to be vaguely in the right direction and Verstappen does what he does.

Kimi Antonelli has climbed up the field to second place behind leader Charles Leclerc, just 0.042 seconds between the Ferrari and the Mercedes.

At Williams, Carlos Sainz is feeling the pressure to get some decent laps under his belt in P20. "Ah the car is a mess, I have no confidence in the rear," the Spaniard tells hid pit wall.

1. Charles Leclerc (Ferrari) - 1:35.291

2 Kimi Antonelli (Mercedes) +0.042

3. Max Verstappen (Red Bull) +0.189

4. Lewis Hamilton (Ferrari) +0.615

5. George Russell (Mercedes) +0.744

Isack Hadjar is furious on the Red Bull team radio as he sits fifth on the timing tower. The word "disgusting" has been said twice by the Frenchman.

Over at Ferrari, Charles Leclerc is picking up where he left off in first practice by banking the quickest time ahead of Max Verstappen with a 1:35.291 on the soft compound.

Image source, Getty Images

The soft tyres are on for the likes of Max Verstappen and George Russell now. The Mercedes of Russell has put down a decent marker after his opening flyer but here comes the Red Bull of Verstappen - and it's the top time for the Dutchman. The gap between the two is just over three tenths.

And now that incident between George Russell and Charles Leclerc - forcing another driver off the track - is going to be investigated after the session.

While the stewards handle that one, more drivers are falling foul of track limits at the Circuit of the Americas, with reigning world champion Lando Norris the latest to have his lap time deleted. The McLaren driver is fourth on the timesheets and still on the hard tyre.

The hard tyre for Lando Norris sees him sitting in third spot, 0.439 seconds off leader Max Verstappen on the medium compound. The world champion reaches the final corner at Cota but his McLaren ends up off the track after running wide.

George Russell, meanwhile, has been handed a black and white flag for forcing another driver off the track. The other driver involved at Turn 18 was the Ferrari of Charles Leclerc, who also looked to be on a slow lap when the pair tripped over each other.