While Max Verstappen topped the timesheets in both of yesterday's sessions, teammate Daniel Ricciardo fears that it is Mercedes that really has the pace here this weekend.
Yet to try the hypersofts, which it has spent most of the year avoiding, the extra soft rubber combined with Mercedes so-called 'party-mode' should see Lewis Hamilton or Valtteri Bottas on top in qualifying claims the Australian.
And while Verstappen was topping the timesheets, Ricciardo was sidelined for much of FP2 with an electrics issue relating to the Renault engine upgrade. The Australian hoping against hope that media speculation over his MGU-K is wide of the mark.
Even with its upgrade the Red Bull will be down on power compared to the Mercedes and Ferrari, but in the twisty first and final sectors the RB14 was continually quickest.
Not for the first time, Kimi Raikkonen was the quicker of the two Ferrari drivers, while Romain Grosjean was 'best of the rest' yesterday, ahead of the Force Indias, Alonso, Leclerc and Hartley.
While Ferrari could well be sandbagging, it's interesting to note that Leclerc does not have the engine upgrade that Vettel and Raikkonen have access to. The German lost a lot of track time in FP2 as his team opted to do back-to-back tests with different floors.
And speaking of engine upgrades, Toro Rosso appear particularly happy with Honda's.
The walls had a couple of drivers wailing yesterday, most notably Carlos Sainz, Stoffel Vandoorne and Lance Stroll, all of whom had encounters a little closer than they would have wished for. Indeed, both sessions were red-flagged at one stage.
Ahead of today's practice session, the air temperature is 19 degrees C, while the track temperature is 31 degrees.
The lights go green but it is almost a minute before Ericsson is the first to head out. He is followed by Grosjean and Sirotkin, all three on different compounds.
Raikkonen is the first of the big guns to head out, but unlike his predecessors he remains out for a second lap. On the hypersofts he posts the first time of the day (1:12.931).
As Raikkonen begins his cool down lap, Vettel and Ricciardo head out, the Red Bull on ultras and the Ferraris on hypers.
Ricciardo crosses the line at 14.686, while Vettel, who is quickest in S3, goes second with a 13.168.
A 13.952 sees Alonso go third, the Spaniard contesting his 300th Grand Prix this weekend.
Raikkonen improves to 12.539 as Hulkenberg goes fourth and Vandoorne fifth.
Vettel improves also, but is now 0.419s off the pace.
Not for the first time, Sainz finds himself up close to countryman Alonso, the Spaniard posting 13.715 to go third, just ahead of the McLaren driver.
A mistake sees Vandoorne head off down the escape road at T3. Unable to spin the car around he performs a 9-point turn in order to return to the track.
Quickest in S1 and S3, Vettel crosses the line at an impressive 12.235, only slightly off Verstappen's FP2 pace.
Bottas goes third (13.218) while Hamilton can only manage fifth (13.567) after a mistake at the final corner.
Ricciardo improves to third with a 12.995.
"Would you like another lap," Alonso is asked. "Er, I think... no," he replies.
Gasly goes fifth (13.334), ahead of Sainz, Hamilton, Hulkenberg, Alonso and Vandoorne.
A 13.653 sees Hartley go ninth.
Twenty minutes into the session and only 2 drivers have posted times, Verstappen yet to even complete an installation lap.
On the ultras, Hamilton improves to third with a 12.598, just 0.363s off Raikkonen's pace on the hypers. The Briton is informed that he is the quickest ultra runner.
Verstappen first timed lap sees the Red Bull driver go third with a 12.552. In the process he becomes the quickest ultrasoft runner.
Proving the durability and pace of the ultras, Hamilton goes second (12.301) having been quickest in the first two sectors.
Put off by a slow Hamilton, Hartley misses the final chicane. The Briton admits that he didn't see the Toro Rosso.
"The objective here for Mercedes is to assess whether or not they can get through Q2 on the ultrasoft," says Pirelli. "On this evidence, would seem that they can."
In the Ferrari garage there is a lot of activity at the rear of Raikkonen's car.
Ocon and Perez go seventh and eighth, thereby becoming best of the rest, both over 0.8s off the pace.
"What the ****, why is he not getting out of the way when we come, what the ****," says a certain driver. We'll let you guess who.
A 13.074 sees Perez leapfrog his Force India teammate.
Hamilton overtakes Gasly in the pitlane before diving into his pit.
Ricciardo switches to the hypersoft as he looks to improve on fifth (12.451).
The Australian posts PBs in the first two sectors but a poor final sector means he fails to improve.
With 24 minutes remaining, Bottas heads out on the hypers.
Quickest in S2, Vettel loses time in traffic in the final sector and fails to improve.
Now Raikkonen goes quickest in S2, and, courtesy of a tow from his teammate, again in S3, crossing the line at 11.763 to go quickest.
Vettel quickest in S2 and Ricciardo in S1, the German crossing the line at 11.648 and the Australian at 12.153 to go third, albeit 0.505s down on the Ferrari.
Raikkonen improves again, but remains second, just 0.002s down on his teammate.
With Hamilton yet to try the hypers, Bottas remains fifth on 12.357.
Behind the big six, it remains Perez seventh, ahead of Ocon, Gasly, Sainz, Hulkenberg, Leclerc, Hartley and Grosjean.
Ah, Hamilton heads out on the hypers.
In the first sector alone he is off the pace, while Bottas posts a PB. The Briton subsequently backs off.
This time Hamilton goes quickest in S1, following up with two PBs as he crosses the line at 11.706 to go third, just 0.058s off the pace. Whether this will be enough to convince him to try the pink-banded tyres in Q2 however remains to be seen.
From out of nowhere, Verstappen produces an 11.599 to go quickest. He was on the hypers.
Vandoorne goes seventh (13.034) despite a weak final sector, while Hamilton misses the apex at T9.
Verstappen posts PBs in the first two sectors but a poor final sector means he fails to improve.
Grosjean leapfrogs Vandoorne with a 13.014 only to be demoted when Hulkenberg posts 12.946.
The battle for seventh continues, with Perez now posting 12.903.
"I'm in the worst possible place," said Sainz, referring to the traffic.
Slo-mo shows Sainz taking a real pounding as he rides the kerbs at the chicane.
The Williams remain at the bottom of the standings, with only Ericsson keeping them company.
The session ends.
Verstappen is quickest, ahead of Vettel, Raikkonen, Hamilton, Ricciardo, Bottas, Perez, Hulkenberg, Grosjean and Vandoorne.
Ocon is eleventh, ahead of Hartley, Alonso, Sainz, Gasly, Leclerc, Magnussen, Sirotkin, Ericsson and Stroll.
The top four are covered by just 0.107, which suggests a thrilling Q3 later this afternoon.
Check out our Saturday gallery from Montreal, here.