The rain that fell all day in Montreal meant that the classification was done in humid conditions similar to those of FP3 on Saturday afternoon, which was led by Alonso.
The alpine rider surprised Sainz to take second place with the last timed lap of Q3, where all the riders had fuel to run throughout the session to take advantage of the drying of the track and the tires working in the range. of optimal work.
Verstappen was untouchable from the start, leading from outside in Q3 and worked the benchmark up to 1m21.299s.
Sainz had looked like he could run Verstappen close after scoring the fastest fastest first sector on his last lap, but while he remained competitive despite losing a fraction to the middle sector, a big slip at the exit of the last curve meant he lost enough time for Alonso to overtake his Spanish compatriot moments later.
Lewis Hamilton took fourth place for Mercedes, who split his strategy at the end of Q3 by installing softs in George Russell’s car, a decision that was counterproductive when the Briton turned the first corners in his first lap. back to slicks.
Russell dropped from the top positions to the eighth position at the end of Q3, with Haas duo Kevin Magnussen and Mick Schumacher leading by pushing the Briton down to fifth and sixth.
Then came Esteban Ocon, while Daniel Ricciardo and Zhou Guanyu completed the top 10.
Zhou is one of several drivers who will face a post-session investigation for his driving during a series of off-track moments during qualifying or trying to find space in traffic during previous segments.
Q2 started with the split drivers to stay in the wet used during Q1 or switch to intermediates, with Alonso using this compound as the leader at the beginning of this segment, just before Sergio Pérez caused a red flag in the barriers in the xicane Turns 3/4.
The Red Bull driver was also in the middle, but blocked the right forward and, after grabbing the other front brake, slipped on the grass and quickly headed for the barriers.
Although his car did not appear to have suffered too much damage, Pérez took a long time to activate the reverse gear and, when he did, he was unable to move backwards, as his nose was buried in the barriers, so that he was asked to turn off the engine, with the barriers at the time. which had to be rearranged once his car had been removed with the crane minus its front spoiler.
When the session resumed after a 12-minute delay, all remaining pilots returned to the interspersed, with a dry line beginning to appear.
Leclerc did not bother to join them, as in Q2 he secured the start ahead of Yuki Tsunoda in the back of the grid thanks to his engine change penalties, but neither did Lando Norris. appeared at the beginning of the remaining nine minutes. of Q2.
Norris reported an engine problem before the red flag confined him to the McLaren garage until just two minutes before the team tried to find and fix the problem, and although he came out for a lap, soon he was ordered to return to the pits after several seconds of rhythm.
Not scoring a time after the red flag, Norris’ return as a banker from the start of Q2 left him 14th and behind the best time of Pérez before his departure, with Leclerc not participating in the middle segment and therefore was knocked out in 15th ahead. of his descent from the grid before the race.
With three cars in trouble or not on the track, only two drivers were at risk of elimination and when Hamilton jumped the order with his last lap, the pressure was on Alex Albon, Valtteri Bottas and Ocon.
The first two scored the personal best with Bottas ahead, but the improvement of Ocon with the last lap of Q2, which Verstappen overcame, knocked out the Finn.
As in Q3 and Q2, all riders ran in general during the initial segment, as times improved by about six seconds when they pulled the water out of the race line, apart from large puddles of stagnant water. at the vertices of the first two curves and the exit of the fork at the end of the turn, with Verstappen ending at the top.
Pierre Gasly was eliminated in 16th position, and AlphaTauri reported a brake problem on this left front wheel, possibly contributing to his late stop in Q1 via the 9/10 Turn chicane.
Gasly only deviated briefly from the track, but as he did not stay to the left of the pylon in the runway before the short descent to the fork, he did not follow the instructions of the race directors and, therefore, it will face post-session research.
Sebastian Vettel was frustrated to be eliminated in 17th place after finishing third in the equally wet FP3 session on Saturday afternoon, with Lance Stroll’s 18th place raising a miserable ranking for Aston Martin.
The other local hero, Williams driver Nicholas Latifi, was knocked out in 19th place, finishing ahead of Tsunoda, who was several minutes ahead at the end of Q1 knowing he would start in the back row anyway.