Andrew Benson
BBC F1 correspondent in Austin

Image source, Getty Images

The weekend has started with a controversy over a device on the Red Bull that can be used to adjust the height of the front of the floor.

Red Bull have responded by pointing out that McLaren have made changes to their rear wing - an extension of the conversations they had with governing body the FIA after the Azerbaijan Grand Prix, where it was seen to flex on the straight.

A McLaren spokesperson said: "As previously mentioned, McLaren proactively offered to make some minor adjustments to our rear wing following the Azerbaijan GP. We have made minor adjustments to all our rear wings since Baku to varying extents to ensure no further issues in this area."

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McLaren chief executive officer Zak Brown talking about Red Bull's ride height controversy in the FIA press conference: "Typically being able to ride a car lower is a competitive advantage, it makes the car quicker most of the time. The FIA, who I think have done a very good job at identifying an element on a single race team, from what we can see, from having looked at all the open-source components, is the only team that has the ability to adjust the ride height from inside the cockpit, whether they have or haven't I have no idea, but having the ability to do it raises questions."

"It's very clear in the regulations and it's a material breach that if you modify your race car, anything that you didn't get permission on or driver comfort, goes very much against regulations so they've decided from what I've read to put a seal on it and at the same time I've heard from the team that you can't adjust it when the car is fully race prepped.

"The car is not always fully race prepped in parc ferme and Sunday mornings, so I think that needs to be unpicked and you know, why do you need to put a seal on something that you can't get to in parc ferme or post-parc ferme conditions? So I still have questions that I need to better understand."

If you missed the big story yesterday in the build-up to the United States Grand Prix, Red Bull have confirmed that they are to make changes to their car as a result of discussions with the FIA.

Rivals had alerted the sport's governing body to a device in the Red Bull cockpit that they believed could be used to adjust the height of the front of the car's floor.

You can read Andrew Benson's full story here

Well, just after first practice when the cars had returned to the garage, representatives from the FIA paid Red Bull a visit. The team's number one mechanic, Ole Schack, then proceeded to demonstrate to the two members of the FIA's technical department how the device is installed into the car and adjusted and more importantly, how it works.

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Liam Lawson's return to Formula 1 will be more of a recovery drive for Sunday's 56-lap race, as the 22-year-old is set to start at the back of the grid in Austin, following a change to a number of engine components which takes him over the amount allocated to each car.

As the pool of parts belong to the car and not the driver, Lawson - who has replaced Daniel Ricciardo for the remainder of the season - has inherited a hefty drop down the order - 60 places in total - for his first grand prix back.

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Carlos Sainz set the pace in his Ferrari in the one and only practice session of this United States Grand Prix, beating team-mate Charles Leclerc by 0.021 seconds on the soft tyre.

Max Verstappen finished third on the timesheets but the Dutchman set his best marker on the softs earlier than the rest of the field. The two McLarens of Lando Norris and Oscar Piastri were fourth and fifth respectively.

Austin's resurfaced track didn't provide the smoothest of rides for some drivers, with Lewis Hamilton and George Russell in the upgraded Mercedes, plus Pierre Gasly in the Alpine, all experiencing spins in the first sector.

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Hello again, folks. Here comes the fourth sprint qualifying session of the 2024 season. And with the title fight on both sides still fiercely competitive, securing an optimal spot on tomorrow's grid could be crucial.

Lights go green for SQ1 at 22:30 BST.

Live commentary is available on Radio 5 Sports Extra, BBC Sounds, at the top of this page using the 'listen live' tab and via most smart speakers. Just ask BBC Sounds to play United States Grand Prix sprint qualifying.

Andrew Benson
BBC F1 correspondent in Austin

Image source, Getty Images

Title rivals Max Verstappen and Lando Norris ended the only practice session at the United States Grand Prix in third and fourth places.

Carlos Sainz set the pace ahead of Ferrari team-mate Charles Leclerc.

Sainz was 0.021secs ahead of Leclerc and 0.253secs quicker than Verstappen, whose time was set earlier in the session than those of Ferrari and McLaren when the track would have been slower.

Norris, who starts the weekend 52 points behind Verstappen in the championship, was 0.013secs slower than the Dutchman.

Mercedes driver Lewis Hamilton, who had a high-speed spin at Turn Four earlier in the session, was fifth, ahead of team-mate George Russell, who himself spun at Turn One.

Read the full report here

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Yeehaw. That was a tough first rodeo for some drivers in Texas.

Right then. This is the point when the weekend goes full throttle, with competitive track action now until the shutters come down on Sunday night.

We'll park up, stretch our legs and come back together for sprint qualifying, which sets the grid for tomorrow's sprint race, at 22:00 BST.

See you shortly!

While we all take a break before sprint qualifying, have a listen to the Chequered Flag podcast.

Eleanor Oldroyd is joined by the BBC team out in Austin. They debate whether Lando Norris can still catch Max Verstappen and land his first driver's title.

Former Haas boss Gunther Steiner is on the pod to give his take on the Max Verstappen swearing controversy and James Vowles talks Williams' progress since he took over as team principal.

Listen on BBC Sounds here

Marc Priestley
Former F1 mechanic on BBC Radio 5 Sports Extra

I think Ferrari are going to be really happy with that. This is a team that hasn't bought major upgrades when lots of the teams around them have and yet they've managed to unlock some pace that has been missing on occasions in recent rounds.

Really unhappy I would say are the early signs at Mercedes and McLaren are probably somewhere in the middle of that where really you would expect them to be right at the front. They're not there yet.

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11. Nico Hulkenberg (Haas)

12. Pierre Gasly (Alpine)

13. Liam Lawson (RB)

14. Alex Albon (Williams)

15. Lance Stroll (Aston Martin)

16. Sergio Perez (Red Bull)

17. Esteban Ocon (Alpine)

18. Valtteri Bottas (Sauber)

19. Franco Colapinto (Williams)

20. Zhou Guanyu (Sauber)

1. Carlos Sainz (Ferrari) - 1:33.602

2. Charles Leclerc (Ferrari) +0.021

3. Max Verstappen (Red Bull) +0.253

4. Lando Norris (McLaren) +0.266

5. Oscar Piastri (McLaren) +0.306

6. Lewis Hamilton (Mercedes) +0.361

7. George Russell (Mercedes) +0.491

8. Kevin Magnussen (Haas) +0.494

9. Fernando Alonso (Aston Martin) +0.510

10. Yuki Tsunoda (RB) +0.711

Jennie Gow
F1 pit-lane reporter in Austin

Well, that is it, practice one done! We go straight into sprint qualifying.

That means all the cars go round the circuit, they take to the start line, they do their practice start in a grid slot.

They pick it themselves, sometimes it's luck of the draw in fairness, they go round and then come back into the pit lane.

Harry Benjamin
BBC F1 Commentator

It is not smooth sailing so far for the Mercedes camps.

Although, Lewis Hamilton closing in a little bit on his second go, now 0.35 off Carlos Sainz's fastest lap time.

The Ferraris are setting the peace in the one and only practice session we'll see this weekend in Austin. Carlos Sainz is carrying a bit more pace than his team-mate Charles Leclerc, leading the way on the timesheets by 0.021 seconds. Leclerc did fall foul of Oscar Piastri's speedy mishap, however, and had to abort his earlier attempt.

Lando Norris is next to cross the line but the title chaser can only manage fourth on the board.

Marc Priestley
Former F1 mechanic on BBC Radio 5 Sports Extra

Pretty much everybody, bar two cars, have the soft tyres on now, low fuel and this really is this one opportunity to find what your car is going to do when you take the fuel out, when you put the fastest tyres on.

That's exactly the situation it's going to be in when we next get onto track for sprint qualifying.

This is where we're going to start to see the order, genuinely compare from one team to another.

Harry Benjamin
BBC F1 Commentator

We're now seeing a bit of a flurry, seeing some fast lap times, perhaps some simulations for qualifying runs.

Max Verstappen fastest... I say that, he's just been displaced by Carlos Sainz!

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There was a brief virtual safety car a few moments ago for Oscar Piastri, who missed the pit entry after carrying way too much speed in his McLaren. The Australian dusts himself off and has another a go, which is still a little bit scrappy, but he does leapfrog a few rivals to go third fastest on his soft run.

Andrew Benson
BBC F1 correspondent in Austin

It was a gimmick and a fake construct based on a false premise, I think.

The idea was it might give someone a chance to really push and, you know, get some excitement and what have you.

It was a complete misunderstanding of the way Pirelli tyres work in Formula 1.