Lewis Hamilton led Sebastian Vettel during the opening practice session for the Canadian Grand Prix in low grip conditions at the Circuit Gilles Villeneuve.
Hamilton clocked a time of 1:13.809 on the Ultrasoft tyres, 0.198s quicker than title leader Vettel, with Valtteri Bottas finishing third fastest, 0.237s behind his team-mate.
Several drivers struggled for grip amid dusty conditions in Montréal, with Kimi Räikkönen, Nico Hülkenberg, Esteban Ocon and Marcus Ericsson all spinning at the Turn 6/7 complex.
Vettel also rotated his car early in the session, through the exit of Turn 1, while an array of drivers locked up heavily at the end of the back straight, with Bottas ending his programme prematurely after making such a mistake.
Räikkönen wound up fourth, while Force India took fifth and sixth, Sergio Pérez ahead of Ocon, the last of the drivers to finish within a second of pace setter Hamilton.
Red Bull posted their quickest times on the Super Soft tyres, having opted against using the Ultra Softs, Max Verstappen seventh and Daniel Ricciardo ninth, the pair split by Williams’ Felipe Massa, also on the red-banded rubber.
Daniil Kvyat rounded out the top 10 in the sole Toro Rosso to set a time, as an engine issue halted Carlos Sainz Jr. on his out lap, ending his session after just five minutes.
There was more woe for McLaren-Honda, with the returning Fernando Alonso stopping on track at the hairpin amid further engine dramas, having completed just one timed lap.
Honda confirmed that a “loss of hydraulic pressure” was behind Alonso’s stoppage, though the cause of the issue currently remains unknown.
Alonso finished the session in 16th position, five places behind McLaren team-mate Stoffel Vandoorne.
Williams rookie Lance Stroll began preparations for his home race in 13th spot, sandwiched by Haas duo Kevin Magnussen and Romain Grosjean, with Hülkenberg a low-key 15th for Renault.
Ericsson took 17th, in front of Jolyon Palmer, who complained of problems with his dashboard early in the session, and Pascal Wehrlein, the German's best time coming on the Soft compound.
