Ahead of the weekend's sole practice session - this being the third Sprint of the season - the air temperature is 16 degrees C, while the track temperature is 37 degrees. It is bright and sunny but cool.

In terms of upgrades, McLaren has a new Front Wing, Coke/Engine Cover, Cooling Louvres, Halo, Rear Wing Endplate, Rear Suspension and Floor Edge. The new front wing design, is aimed at better flow conditioning across the operating range resulting in improved aerodynamic load delivery, while the revised bodywork package features additional cooling exits aimed at improved aerodynamic flow conditioning towards the rear of the car. As part of the new bodywork package, multiple cooling louvre options are available to cover the full range of ambient temperatures expected at this and future events. A new winglet on top of the halo is aimed at improving management of aerodynamic flow around the cockpit and central engine cover, while a modification to the rear wing endplate geometry results in a change in load distribution and increase in local aerodynamic load. The small modification to the rear suspension fairings is aimed at improved aerodynamic flow conditioning and load generation around the rear corner and diffuser, while iteration on floor edge devices is aimed at improved overall floor conditioning and aerodynamic load generation on the floor and diffuser.

Mercedes has a new Front Wing, Front Wing Endplate, Front Corner, Floor Board, Floor Corner, Floor Body and Rear Corner. Running the front wing elements into the footplate, and adding strakes, will result in more robust flow structures, improving flow to the rear of the car and gaining downforce. Reduced upper lip camber improves flow structure robustness throughout the operating envelope, improving the onset flow to the rear wing. Due to the high braking demands of Montreal - increasing the duct inlet and exit size increases mass flow feeding the discs resulting in more cooling, while reprofiled elements will improve local pressure distribution and reduce separations at the extremes of the operating envelope, resulting in increased local load. Re-optimisation of the floor corner slot arrangement to increase local load and to also improve flow into the diffuser and hence rear load. Reprofiling the diffuser roof and sidewall will improve the surface flow quality throughout the operating envelope and generate more local load, while the chord and position of the rear cake-tin winglets have been re-optimised to improve local flow control and performance of the diffuser.

Red Bull has a new Front Wing, Front, Floor and Engine Cover. Both the second and third front wing elements forming the flap assemblies have been revised to shift the aero balance range available for the upcoming circuits, the next two of which demand more brake assembly cooling and to offer this an enlarged exit duct has been produced to enhance the cooling. To further optimise both the bib and forward floor devices, the former has a trim applied and the latter mildly increased camber resulting in the local load increasing, while, given the forecast for Montreal, a closed radiator exit panel has been created with the louvre steps necessary for the race in Miami now closed.

Williams has a new Front Corner, Front Suspension and Exhaust Tailpipe. To suit the demands of the circuit, a new FBD geometry has been introduced which offers an increased level of overall brake system cooling, while, in concert with the updated FBD geometry, new suspension cladding will be available to improve the local interactions on the front corner and hence downstream across the rest of the car. Following on from the update introduced in Miami, a further step on the exhaust system will be evaluated which offers an improved coupling with the surrounding aerodynamic components.

Racing Bulls have a new Floor Body, Rear Corner, Beam Wing and Exhaust Tailpipe Bracket. The new floor geometry will result in an efficient downforce increase generated by the underbody of the car, across a range of operating conditions, while, working in conjunction with the floor update, the changes to the rear corner devices improve the flow management at the back of the car. Supporting the changes made to the floor and around the exhaust, the beam wing changes help extract additional load from the rear wing assembly, while the tailpipe bracket update improves the flow management around the centreline of the car as part of the surrounding changes on the beam wing and floor.

Haas has a new Sidepod Inlet, Coke/Engine Cover, Floor Body, Rear Suspension and Rear Corner. The revised bodywork enables a more pronounced undercut along the lower surfaces, which, combined with increased top-surface downwash, channels higher-energy airflow towards the rear of the car, allowing the bespoke floor design to operate more efficiently. The new floor was developed in conjunction with the updated bodywork. Its geometries are optimised to guide higher-energy airflow through the floor volume, enhancing mass flow and stability, and promoting more efficient extraction and overall load generation. The updated floor and bodywork required a realignment of the suspension fairings, enabling improved flow conditioning in this region and extracting additional performance from the overall package, while the modified incoming flow field required a realignment of the inboard drum devices to maintain their aerodynamic effectiveness and ensure consistent performance within the updated overall flow conditions.

Audi has a new Front Corner, Floor Diffuser, Cooling Louvres and Rear Corner. The changes to the front corner offer increased brake system cooling flow for the big braking zones of this specific track, while the diffuser geometry update with a further evolution of its shape is aimed at increasing aero load efficiently at the rear end. For this event new sidepod louvres are available to allow fitting more efficient cooling option, while changes at the rear corner offer increased brake system cooling flow for the big braking zones of this track.

Alpine has a new Floor Body and Rear Wing. The completely new floor geometry released at this event has the objective of increasing aerodynamic performance and efficiency across all operating conditions, while, as part of the rear wing development programme, geometrical adjustments to the latest rear wing are also introduced.

Cadillac has a new Front Corner and Diffuser. The leading edge lip profile of the FBD has been revised to improve overall aerodynamic loading, whilst internal duct and exit geometry revisions increase brake cooling capacity. A lower edge trim has been applied to the diffuser winglet cascade, and the hanger detail has been revised to increase local aerodynamic load at the rear of the car.

Neither Ferrari nor Aston Martin has brought any upgrades.

The pitlane opens and Hulkenberg leads the way, or rather he doesn't, as he appears to have an issue. Consequently, Alonso is first out, followed by Perez, Bearman, Ocon and, finally, Hulkenberg.

As more cars head out all three compounds are in use.

Piastri sets the first realistic benchmark, the Australian crossing the line at 19.489.

"My throttle is not working," reports Colapinto though he is able to coast back to the pits.

A 17.432 sees Verstappen go top, ahead of his Red Bull teammate, while Sainz goes third with an 18.828.

Norris locks up and misses the final chicane, while Verstappen runs a little wide exiting Turn 14 and kicks up a cloud of dust.

"I have an issue, I've lost power steering," reports Lawson as he stops at the first chicane.

The VSC is deployed.

Just before Lawson's issue, Verstappen had improved to 15.895.

"Initial impressions on downshifts," Verstappen is asked. "They feel better, especially in the lower gears," he replies. "Locking feels better too."

Unable to remove the RB to safety, the session is red-flagged.

At the time of encountering his issue, Lawson had just posted the fourth best time of the session.

The session resumes with 44 minutes remaining and, understandably, due to the lack of 'testing' time, the drivers are keen to get back to work, Piastri leading the way, ahead of Albon, Bortoleto, Sainz and Russell.

As Race Control announced that the session will be extended by 4 minutes, Alpine reports that Colapinto has a power unit issue.

Antonelli goes third with a 16.734, but is leapfrogged by his teammate who stops the clock at 16.264.

Hamilton improves to ninth with an 18.099, the majority of the fastest times being set on the hards.

As Alonso (softs) goes fifth, Antonelli goes second with a 15.994, only to be demoted by his teammate again, Russell banging in a 15.893.

A 15.806 from Piastri.

A number of drivers have been off track due to the dusty surface, their excursions usually resulting in even more dust being deposited on to the track.

"I'm smashing the ground at every bump, it feels like 10 in the ride height, it is awful," reports Ocon.

Piastri raises the benchmark with a 14.963.

Oh dear, Albon has clouted the wall exiting the chicane at 6/7. The left-hand side of his car is badly damaged and as he climbs out of it the session is red-flagged. Though he looks fine, albeit a little frustrated, the Medical Car is deployed.

The Thai driver was ninth quickest at the time of the incident, which, it is understood, was due to him trying to avoid a groundhog.

Of course, this second stoppage is biting into the drivers' running, and there is only so much time that Race Control can 'give back'.

The session resumes at 13:13 (local time), as the session is extended by 15 minutes.

Russell is first out, followed by Verstappen, Antonelli, Hadjar and Leclerc. The white-banded rubber remains the most common choice.

"The steering has suddenly got a lot heavier," reports Verstappen.

Quickest in S2, Russell goes second with a 14.976 as Hamilton goes third with a 15.405.

A 15.400 puts Leclerc third, 0.005s up on his Ferrari teammate.

Still on the soft, Alonso improves to seventh with a 16.218, albeit 1.255s off the pace.

Lindblad, on the mediums, goes sixth with a 15.452 as Russell reclaims the top spot with a 14.560, 0.110s up on his teammate.

Stroll, also on softs, goes sixteenth with a 17.748, as Norris improves to fourth with a 15.192 - though the driver tracker shows him stuck at the end of the pitlane.

Both Mercedes drivers really pushing, Russell improving to 14.444 only to be demoted when his teammate stops the clock at 14.392.

Having lost downforce due to running close to a car ahead, Gasly misses the second chicane. The Frenchman is currently fourteenth, his teammate sidelined for the remainder of the session.

"I'm getting these weird snaps a lot," reports Verstapepn. "It's really upsetting me."

Verstappen is the latest to miss the second chicane, as Hulkenberg improve to fifteenth.

Hamilton misses the final chicane as Antonelli, Norris and Verstappen have times deleted also.

With 18 minutes remaining, Russell is the first of the big guns to switch to the softs as attention turns to the Shootout.

As one would expect, the Briton goes purple in S1, going on to be quickest in the second sector also. At the line it's a 13.850, having lost time exiting the hairpin.

Now Antonelli heads out on the red-banded rubber.

The teenager goes quicker in S1, but loses pace in the second sector, and as Piastri heads out on softs, the world championship leader goes quickest with a 13.402, 0.448s up on his Mercedes teammate.

On softs, Leclerc goes third with a 14.355 as Piastri goes fifth (14.963), despite going quickest in the second sector.

As the replay shows Piastri running wide in the final chicane, Russell too suffered an off, albeit at Turn 1.

Russell improves but remains second, now 0.142s off the pace, while Norris locks-up at the hairpin.

Hulkenberg improves to eighth with a 15.698.

"Got pretty reasonable flat-spots now," reports Piastri.

Hamilton improved to third with a 14.176 as replay reveals Russell spinning at Turn 1.

"I think I brushed the wall," he reports.

The session is red-flagged for a third time as we see Ocon missing his nose cone, and lots of debris strewn across the track.

Replay shows him losing it after applying the power as he exited Turn 2. It was a heavy hit with the barriers, but he makes it back to the pits.

There will be no further extension to the session's running time, but the drivers will be keen to go out, even with less than a minute remaining, in order to carry out a practice start.

To add to Ocon's woes he has been noted for leaving the pit exit on a red light.

First blood to Antonelli, who finishes ahead of Russell, Hamilton, Leclerc, Verstappen, Norris, Piastri, Lindblad, Hulkenberg and Alonso.

Bortoleto is eleventh, ahead of Hadjar, Ocon, Albon, Sainz, Gasly, Stroll, Lawson, Bearman, Bottas, Perez and Colapinto, who didn't post a time.