Andretti Global’s Colton Herta was fastest in a frantic opening practice on the Streets of Toronto.
The California native delivered a flying lap of 1m01.0399s around the bumpy and tight 11-turn, 1.786-mile temporary street circuit around Exhibition Place. Last year’s FP1 best time was a 1m00.8075s.
The No. 60 Meyer Shank Racing Honda of Felix Rosenqvist was second overall with a best of 1m01.332s, with Chip Ganassi Racing’s Marcus Armstrong third with a run of 1m01.7791s.
Six-time IndyCar Series champion Scott Dixon was fourth, ahead of Graham Rahal in fifth.
AJ Foyt Racing’s Santino Ferucci was sixth, ahead of reigning and two-time series champion Alex Palou.
The initial 15 minutes of the 45-minute all cars session only saw 15 cars on track, with Rahal Letterman Lanigan Racing’s Christian Lundgaard setting the early benchmark at 1m03.2641s on the harder primary tyres.
Rahal was the first to knock his team-mate off the top spot, but Team Penske’s Will Power reset the mark with a lap of 1m02.6980s with 27 minutes left in the all-cars segment.
It was only two minutes later that Marcus Ericsson slowed with a plume of smoke erupting off the back of his No. 28 Andretti Global Honda. He later stated on the Peacock broadcast that he “just lost power” and was left watching his team-mates for the remainder of the session.
The top spot rotated once more as Palou produced a flying lap of 1m02.3310s, but then was knocked off after Rossi nailed a quick run of Rossi 1m02.2747s.
Power spun in Turn 10 with 15 minutes left in all cars, but got self-started and continued on. The No. 78 Juncos Hollinger Racing Chevrolet of Agustin Canapino spun moments later at the exit of Turn 8.
Rosenqvist set a lap of 1m02.2467s to go to the top of the leaderboard. In the final minute of the all-cars portion, Herta set a 1m02.2189s to register the quickest time but was dethroned after Palou nailed a 1m02.0804s. But Herta responded with a 1m01.8906s to return to the top spot.
After a brief five-minute break, the remaining 20 minutes was halved as the field split into two groups with running on the softer alternate tyres.
Rahal went out and set an early mark of 1m02.4593s in the split group, but was fuming over the handling of his No. 15 RLL Honda, calling in over the radio: “The rear of my car is garbage. Absolute garbage.”
Chip Ganassi Racing’s Marcus Armstrong delivered a 1m02.1155s lap with six minutes left to set the mark for Group 1. Herta then went fastest with 1m01.0399s flying lap in the last minute, with Rosenqvist then taking the second spot at 1m01.3323s.
Group 2 began with trouble for Rossi, who brought out the red flag after clipping the tyre barrier in Turn 9 and ripping the left-front corner off the car, pounding the wall. He was seen removing the right glove and holding his hand and wrist following the impact.
After rookie Hunter McElrea, making his IndyCar debut with Dale Coyne Racing, took to the escape road, fellow rookie Linus Lundqvist drove hard into Turn 8 and buried his No. 8 Chip Ganassi Racing Honda under the tire barrier to bring out another red flag.
The session ended under the red flag, with McElrea setting the quickest time of the group at 1m02.6102s.
