Max Verstappen and Charles Leclerc were more than a second clear of the pack in a wet final practice for the Canadian Grand Prix that saw Carlos Sainz in the barrier.
The Dutchman proved the class of the field with a series of laps late in the session, bisected by a mistake from Sainz into the first corner which drew the red flag.
Only Leclerc was within touching distance in what proved to be an important outing ahead of qualifying.
Though the race is forecast to be dry, running on the wet circuit had value as conditions were not expected to dry for the remainder of the day.
For the most part the circuit was ready for intermediate tyres as Free Practice 3 began, though puddles existed and encouraged the use of the extreme wet tyres.
The early running, set by Kevin Magnussen, underscored how tentative drivers were being; his 1:34.797s around 20s slower than the pace during Free Practice 2 on Friday.
Fernando Alonso was the first to brave the intermediate tyres, quickly followed by his Aston Martin team-mate, Lance Stroll, eight minutes into the 60-minute session.
Conditions had hardly changed from when practice began, as shown by Yuki Tsunoda who spun exiting Turn 4.
The Scuderia AlphaTauri driver, who'd baulked Alonso at the hairpin earlier on, somehow avoided impacting the walls.
On the intermediate tyres, Alonso was faster than anyone through the first third of the lap, but overshot at Turn 8 as he struggled for grip.
Standing water remained around the Turn 10 hairpin, especially in the acceleration zone making the switch to shallower grooved rubber a brave one.
Those who could make them work showed the intermediates were the faster tyre; Valtteri Bottas clocked a 1:18.968s on the green-walled tyres.
Alonso was unperturbed and was set to go fastest on his second timed lap, going purple to the second split, only to lock up into the final chicane to ruin the lap.
He finally managed to complete a lap at the third time of asking, a 1:27.517s that left him 1.4s quicker than anyone else on track.
On the racing line, the track was clearly improving, with far less water and few puddles remaining after 20 minutes.
Still, drivers were being routinely caught out; Tsunoda, Stroll, Nico Hulkenberg, Pierre Gasly, Alex Albon, and Sergio Perez all coming unstuck.
Finding clear track was also an issue, Sainz twice hindering the progress of Albon.
The worst of those came approaching Turn 13 when the Spaniard worked his way by team-mate Charles Leclerc and allowed one of the Red Bull's through.
However, he then impeded Albon who arrived on the scene, taking to the inside of the circuit as the Ferrari steered right, seemingly oblivious to the approaching Williams.
That caught the eye of the stewards who confirmed they'd investigate post-session.
Soon after, the red flag was shown when Sainz crashed at Turn 1.
The Ferrari was left without a nose, and an askew rear wing after he lost the rear under braking into Turn 1, spinning into the barrier.
He sat second fastest at the time with concerns immediately raised for the team's ability to repair the SF-23 in time for Qualifying.
Running resumed with 23 minutes remaining, nine minutes after it had been halted.
Fastest prior to the stoppage, Verstappen pressed on after it, improving to a 1:23.779s.
Mercedes had struggled for tyre temperature on the intermediate tyres earlier, but George Russell suggested the team had found something as he popped up to fourth.
Albon too demonstrated Williams was able to generate the temperature he needed, as did Lando Norris for McLaren.
The improvement from drivers was largely down to three factors; the improving conditions, increased confidence, and tyre temperature.
Of those, confidence was key; by pushing on the tyre temperature increased which created more confidence, a positive feedback loop exploited by Verstappen as he continued to improve to 1:23.106s.
It also led to significant gaps between team-mates; Verstappen was 2.9s faster than Perez, with a similar gap between Albon and Logan Sargeant.
With 10 minutes remaining, the weather deteriorated once more, though curiously that didn't stop Hamilton from improving on his best.
Leclerc was the only driver willing to take the risk of heading back out, though only so he could complete a practice start before returning to the pits.
There, he watched the clock run down with the rest of the pack, leaving Verstappen fastest by 0.291s from the Monegasque driver, with Alonso third best, 1.377s away from the outright pace.