Formula 1 championship leader Lewis Hamilton topped the timesheet in FP1 ahead of the Canadian Grand Prix, while second-placed Valtteri Bottas sealed a Mercedes one-two at the top.
The Mercedes duo ended up 0.8 seconds clear of the rest, with Ferrari’s Charles Leclerc closest to the Silver Arrows in third.
Bottas and Hamilton posted identical times 35 minutes into the session to begin a dominant spell in first and second.
The two gradually reduced their times, with Hamilton notching a 1m12.767s to beat Bottas’ best effort by 0.147s.
Leclerc, who was knocked out of qualifying at the Monaco Grand Prix in Q1 following a strategic misstep by Ferrari, ended the session just 0.025s ahead of Red Bull’s Max Verstappen.
Sebastian Vettel was fifth, despite suffering a lock-up at the hairpin which led to a half-spin.
He was only narrowly clear of sixth-placed Kimi Raikkonen, who propelled his Alfa Romeo up the timesheet in the closing stages of the session.
His rookie team-mate Antonio Giovinazzi was the first driver to hit the wall. Running deep into Turn 8 and subsequently taking too much kerb through Turn 9, he spun and plucked the left-rear tyre into the concrete wall.
A virtual safety car followed as the marshals recovered his car. Giovinazzi lost the remaining 30 minutes of the 90-minute session.
Carlos Sainz Jr was seventh for McLaren ahead of Renault’s Daniel Ricciardo.
Racing Point’s Sergio Perez and Haas’ Kevin Magnussen rounded out the top 10.
Red Bull’s Pierre Gasly threatened to graze the Wall of Champions early in the session. He also endured a snap of oversteer into Turn 1 which forced an off-road excursion through the run-off area en route to 13th place.
Williams reserve driver and Formula 2 championship leader Nicholas Latifi replaced Robert Kubica for FP1.
The Canadian ended up bottom of the timesheet but was a slender 0.2s adrift of team-mate George Russell.