Lewis Hamilton claimed the early initiative by setting the quickest time in first practice at the Canadian Grand Prix.
The Mercedes driver posted a 1m13.809s with around 20 minutes to go, leading the Ferrari of Sebastian Vettel by 0.198s as less than half a second covered the two teams.
Force India had a strong morning claiming fifth and sixth, with Sergio Perez ahead of Esteban Ocon, that was due to in part to a muted morning for Red Bull, who completed fewer laps than most and saw Max Verstappen in seventh and Daniel Ricciardo wait until late to move up to ninth.
Felipe Massa confirmed Williams should enjoy a much stronger weekend than in Monaco in eighth, as Daniil Kvyat completed top 10 for Toro Rosso.
The Russian would do all the work for the Italian team, however, as his team-mate, Carlos Sainz pulled off the circuit exiting the hairpin on his installation lap due to a suspected engine failure.
That would start what was an eventful session, as a very dusty Circuit Gilles Villeneuve saw all drivers struggling for grip.
A number of spins occurred, including both Ferraris in the first 25 minutes, Raikkonen lost the rear of his car applying the throttle exiting Turn 7 while Vettel spun after his car was unsettled on the kerb between Turn’s 1 and 2.
Many others would follow suit in the same areas, however, including Nico Hulkenberg, Esteban Ocon and Marcus Ericsson all the Turn 6 and 7 chicane.
Known as one of the toughest tracks of the year on the brakes, that would be proven too with several drivers misjudging their braking points and forced across the run-off area at Turn 8 and the final chicane.
Fernando Alonso, fresh from his participation at the Indy 500, would return to yet more poor reliability as a hydraulics issue forced him to stop at the hairpin in his McLaren. The performance of team-mate Stoffel Vandoorne, claiming 11th, gave some optimism to the British team who are expected to struggle down Montreal’s long straights.
Lance Stroll had a reasonable first outing at his home circuit in 13th, but, further down the order, Renault had a difficult morning with Nico Hulkenberg 15th and Jolyon Palmer, who had minor electrical problems early, in 18th, battling with the two Saubers.