Ahead of today's opening session the air temperature is 24 degrees C, while the track temperature is 29 degrees. It is bright and sunny.

In terms of updates, McLaren has a new Front Suspension, Front Corner and Rear Corner. The revision to the front suspension fairings is aimed at an overall improvement of flow conditioning which results in an aerodynamic performance gain, while, complementing the aforementioned changes, the aerodynamic devices on the front corner have been adopted to allow full exploitation of the flow conditioning improvement. The alternative rear suspension geometry requires a revision of rear corner aerodynamic surfaces to maintain clearances as well as aerodynamic performance.

Ferrari has new Floor Fences, Floor Body, Floor Edge and Diffuser. These are not event specific, the floor package features updated front floor fences targeting an enhanced vorticity released downstream. The reshaped boat and tunnel expansion have been subsequently re-optimized, together with the floor edge loading and diffuser volume distribution, leading to an overall load gain across the car operating envelope

Red Bull has a new Floor Edge. Basically, a new edge wing is being deployed intended to maintain the established flow stability and improve the load extracted from this region of the floor.

Mercedes has a new Front Corner and Coke/Engine Cover, both of which are circuit specific. On the front corner there is an increased brake duct inlet and exit area to cover off the high brake duty that is typically seen at this circuit. Meanwhile, the engine cover sees an increased bodywork exit area designed to increase mass flow through the sidepod radiator and hence provide the additional cooling required for this circuit.

Racing Bulls have brought a new Front Wing and Rear Wing. The flap on the front wing has been changed to improve local flow conditioning and help increase aerodynamic performance across a range of conditions, while the upper rear wing has been changed to meet the needs of the target downforce & efficiency level for the circuit.

Stake has a new Floor Body and Rear Wing. Modifications to the floor are targeted at improved flow field conditions for the underfloor from front to back, gaining some efficient downforce. The new rear wing assembly is suited for higher downforce tracks. It features a reshaped geometry with a more efficient load distribution which will cover a variety of tracks until the end of the season.

These are the only updates this weekend.

There are two reserve drivers on duty in this session, Dino Beganovic replaces Leclerc at Ferrari, while Alexander Dunne is in Norris's McLaren.

The lights go green and Hamilton leads the way, followed by Dunne, Beganovic, Antonelli and Ocon.

As more drivers head out all three compounds are in use. That said, it's mostly hard and medium with the majority of teams splitting their strategies.

Lots of flo-vis and aero rakes, that on the Ferrari particularly large.

Of the first wave, Russell is quickest (7.140), ahead of Sainz, Verstappen, Hulkenberg and Albon.

Stroll goes top with a 6.853 while Alonso makes it an Aston 1-2 with a 7.072.

Russell retakes the top spot with a 6.537 as Dunne complains of hearing three different voices on his radio, no doubt one is the local taxi firm.

Verstappen is unhappy following a number of lock-ups both front and rear.

Antonelli goes third with a 6.908 but is demoted when Verstappen posts a 6.723 to go second.

"I'm struggling with front locking," reports Antonelli, as he improves to second with a 6.342.

Alonso goes fourth (6.791), ahead of Albon, Stroll, Gasly and Lawson.

Both Mercedes drivers are on the hards - as is Bortoleto who goes third - while Verstappen is on mediums.

"The brake is really poor," says Tsunoda as he goes off after both front wheels lock-up.

A 6.017 sees Sainz go top on the mediums, as Russell switches to softs, the first driver to do so.

"We've got an issue with the gearbox," Hamilton is informed, as Albon runs wide in Turn 9.

Back in the garage, mechanics swarm over the rear of Hamilton's car. In the adjacent garage, Beganovic's car is up on its stand with the floor having been removed.

Russell raises the bar with a 5.776.

As Piastri goes fourth (6.344) on the mediums, Antonelli improves to third with a 6.130.

Bortoleto, Hulkenberg and Bearman switch to the red-banded rubber as Dunne posts his first time of the day, an 8.520.

Russell improves to 5.542 as Bortoleto goes second with a 5.915.

More and more drivers switch to the softs.

Alonso spins at Turn 10, briefly bringing out the yellows. It was the Spaniard's first lap on the softs. "OK, that was the worst out-lap we can do," he says. "Good to do it in FP1."

Gasly goes second with a 5.780, watched on by Flavio Briatore.

Quickest in S1, Tsunoda can only manage tenth overall (6.338).

Hadjar improves to fifth with a 6.110.

PBs in all three sectors see Piastri go third (5.697) as Dunne improves to fourteenth.

Verstappen goes second with a 5.607, 0.065s off Russell's pace.

A lock-up sees Ocon make full use of the run-off at Turn 1. "Flat spot, front-left, I think," he reports.

With 18 minutes remaining, both Ferraris are back on track. Beganovic is currently seventeenth and Hamilton last.

Dunne improves top fourth with a 5.766. Very, very impressive from the youngster, who is only fractionally off Piastri's pace.

As Alonso and Hulkenberg switch to hards, Piastri reverts to the mediums, as does Verstappen.

Laurent Mekies reveals that Lawson is running the front wing upgrade while Hadjar has the rear wing upgrade.

Hamilton goes ninth (6.099) on the softs.

"It's raining in Turns 3 and 4, very light," reports Piastri. He is informed that it will only be a few light drops, nothing to worry about.

"Ah, man, this traffic," complains Antonelli. "It's a short track, so the gaps are small," he is told.

As the clock counts down, all bar Hulkenberg are on track. Though the German subsequently heads out.

The session ends. Russell is quickest, ahead of Verstappen, Piastri, Dunne, Gasly, Bortoleto, Albon, Sainz, Hamilton and Hadjar.

Antonelli is eleventh, ahead of Hulkenberg, Stroll, Alonso, Lawson, Colapinto, Tsunoda, Beganovic, Ocon and Bearman.

A good start to the weekend for Mercedes, particularly Russell, while Verstappen will also be feeling good. Not the best start for Ferrari, while McLaren must be pleased at Dunne's highly impressive debut.

A promising start to the weekend.