Ahead of today's opening session the air temperature is 30 degrees C, while the track temperature is 39 degrees. It is bright and sunny.

There is very little in terms of updates with only three teams bringing anything.

Alpine has a new floor edge and Alfa Romeo a new floor body, Mercedes, with its last upgrade of the season, has a new front wing, floor fences and edge and rear wing endplate.

However, while the updates might be thin on the ground there are a number of young drivers on duty this morning. There's Alex Palou at McLaren, Robert Schwartzman at Ferrari, Logan Sargeant at Williams, Theo Pourchaire at Alfa Romeo and Antonio Giovinazzi at Haas.

We're expecting this session to be busy because this afternoon's extended session is mostly given over to tyre testing as Pirelli tries its 2023 compounds.

Indeed, ahead of the green light there is already a queue at the end of the pitlane.

First out is Stroll, followed by Gasly, Tsunoda, Giovinazzi, Vettel and Norris. All three compounds are in use as more drivers head out.

Among the early risers are the Mercedes pair.

"It smells like barbecue in the car," reports Gasly as Perez heads out, leaving Verstappen, Zhou and Sargeant as the only drivers yet to appear.

Stroll gets things underway with a 46.292, however this is soon beaten as Sainz crosses the line at 41.381.

Hamilton's Mercedes is sporting a large sensor at the rear, the German team no doubt evaluating those updates.

Palou is told to get clear air to Alonso who is ahead, "pull over if you need to," he is told.

Oh dear. Giovinazzi is in the barrier at Turn 5.

The session is red flagged.

The Italian is at the wheel of Magnussen's car.

After several attempts he finally makes his way the pits, his car showing obvious signs of front wing damage.

Replay shows the Italian losing the rear on entry to the corner, possibly distracted by a car just ahead or maybe one of the circuit's notorious bumps..

"We think there's some right rear damage also," he is told.

The session resumes with 49:38 remaining. Norris (medium) is currently quickest (40.673), ahead of Sainz (soft), Ocon (medium), Vettel (hard) and Schumacher (soft).

Alonso goes top with a 39.555 but is instantly leapfrogged by teammate Ocon who crosses the line at 38.810.

Quickest in all three sectors, Verstappen stops the clock at 38.272.

"I'm already losing rear grip," reports Sargeant as Haas reveals that due to clutch damage Giovinazzi's session is at an end.

Meanwhile, having taken on new internal combustion engines, Perez and Zhou appear to be facing grid penalties.

After 22 minutes, Pourchaire is the only driver yet to post a time, while Palou (11th) is the highest placed rookie.

Verstappen (soft) improves to 37.462 as Perez goes second, ahead of Vettel, with a 38.345.

Sainz splits the Bulls with a 38.287 as Schwartzman improves to 14th with a 40.541 on softs.

"This car is insane," declares Palou having switched to the soft tyre.

Vettel improves to second with a 38.041 as teammate Stroll posts a 38.408 to go fifth.

A 38.579 sees Russell go sixth.

"Starting to get some lock-ups in the front," reports Schwartzman.

"I hit the kerb and the car bounced," says Ocon as Hamilton, having dumped the sensor, appears to be going for a quick lap. Indeed, he improves from 17th to 2nd with a 37.645, 0.183s down on Verstappen.

Quickest in S1, Alonso remains third after making a mistake and pushing too hard in the final corner, appropriately named Andretti.

Stroll goes quickest with a 37.460.

Schumacher is told to pit as he has a sensor issue.

Quickest in all three sectors, Sainz bangs in a 36.857, eclipsing Stroll by 0.603s.

Perez is backing me up, complains Sargeant. "Keep it safe," he is told, "it's fine, stay there."

Hamilton improves to second with a 37.332.

With 10 minutes remaining, it is understandable that the rookies fill the lower positions on the timesheets, with Palou 16th, ahead of Schwartzman, Pourchaire and Sargeant.

Alonso, Gasly, Vettel and Ocon have completed the most laps (18).

Having gone quickest in S2, a mistake at Turn 11 sees Verstappen cross the line at 37.081 to go second, 0.224s down on Sainz.

With 5 minutes remaining, all bar Giovinazzi are on track.

Tsunoda improves to 14th with a 38.898. Teammate Gasly is currently 8th.

The session ends. Sainz is quickest, ahead of Verstappen, Hamilton, Stroll, Perez, Alonso, Russell, Gasly, Norris and Vettel.

Ocon is eleventh, ahead of Zhou, Albon, Tsunoda, Schumacher, Schwartzman, Palou, Pourchaire, Sargeant and Giovinazzi.

Check out our Friday gallery from COTA here.