Turn that frown upside down, Max. Two purple sectors in the middle of the lap and the final stretch puts the two-time world champion quickest with a 1:36.223 on the softs.

Rejoice. Mick Schumacher is on a set of soft tyres and is tagged back into the fold with 10 minutes to go. Max Verstappen is third on the time sheets but the Dutchman is not happy with the conditions as the clock ticks down.

1. Sergio Perez (Red Bull) - 1:36.578

2. Lewis Hamilton (Mercedes) +0.11s

3. Max Verstappen (Red Bull) +0.128s

4. Charles Leclerc (Ferrari) +0.187s

5. Carlos Sainz (Ferrari) +0.316s

Jolyon Palmer
Former Renault driver on BBC Radio 5 Live

So many drivers struggling with the rear, it's windy and the temperature is quite high as well.

Will we see a Mercedes take a win in the four races remaining of the season? George Russell's best time so far is only good enough for sixth place on the time sheets after slipping across the Austin track, while second-placed Lewis Hamilton is still trying to chop into leader Sergio Perez's top marker.

Ian Fergusson, BBC weather forecaster, notes: "This strong southerly wind remains a major feature for qualifying and for the race tomorrow. It adds various tailwind and crosswind components especially between turns 1 to 10, but its gusty nature adds unpredictability lap-to-lap. Thankfully, the weekend will stay dry. I suspect fans have had more than enough of rain jeopardy this season...!"

Peter: I'm getting a bit fed up with this "grid penalties" malarkey ... surely there is a better way of handling this than just messing up every grid!

Bernard Starkey: There's no room for a groundbreaking innovation that will shuffle the order, as there was in the past. It's all about marginal gains.

Mick Schumacher was told his repairs would only take around 15 minutes. He's had to sit in the garage for a little bit longer than that but finally, is it good news for the German driver?

Jack Nicholls
BBC Radio 5 Live F1 commentator

The crucial thing will be if they (Mercedes) can qualify to get themselves in the mix, the crucial thing is the race pace is what brought them towards winning contention.

If they can start in and amongst the Verstappen's, they will be ahead of Leclerc which will be a big boost for Hamilton and Russell, if they can start ahead of Perez as well, then they are right in the mix. If their race pace is better than qualifying pace like usual then Mercedes think this should be their best chance of winning probably for the rest of the season.

Fernando Alonso is pounding around the circuit to the delight of the US crowd but the Alpine man is grappling with the gutsy conditions. Alonso has been quickest in the first sector so far but as he comes to the final corner he fails to move up the order and stays in sixth with a 1:37.439 on the soft tyres.

Daniel Ricciardo has rejoined the action and his McLaren engineer asks if he's happy with the brake pedal. "I think it feels OK now," says the Honey Badger.

Back to the track action and the top two spots have changed hands. No longer are they occupied by Max Verstappen and Charles Leclerc, with 28 minutes to go, Sergio Perez is the quickest man of the pack with a 1:36.578, followed by the upgraded Mercedes of Lewis Hamilton, just 0.11secs behind.

So, Charles Leclerc and Fernando Alonso will also be shifting to a new grid position come Sunday's race.

Daniel Ricciardo's engineer reports that "everything looks normal in the data with the brakes" - can the Australian give a bit more feedback? "Feels really stiff," comes the reply. "There's no bite."

Jennie Gow
BBC Radio 5 Live pit-lane reporter

Fernando Alonso has taken another internal combustion engine, his fifth of the season, as has Charles Leclerc so they will both pick up penalties. Leclerc also using a fifth turbo charger of the season as well.

Grid penalties we know for sure this weekend are heading the way of Red Bull's Sergio Perez and Alfa Romeo's Zhou Guanyu after taking new internal combustion engines for Sunday's race.

Any other drivers want to join the grid penalty gang?

If there's one weekend Daniel Ricciardo would want a massive slice of luck on his side, it's his spirit animal home of Texas. Horsey McHorse might need to put a shift in here.