Lewis Hamilton led George Russell as Mercedes continued their improved form with a one-two finish in Practice Two at the Canadian GP.
Fresh off the back of their double podium in Barcelona, Hamilton topped the timesheets with a 1:13.718 and Russell was just 0.027s off his team-mate.
Carlos Sainz had led a significant part of an extended 90-minute Practice Two - after Practice One was severely disrupted by CCTV issues at the circuit - but ended up with the third fastest time, a further tenth of a second back.
Team-mate Charles Leclerc was sixth fastest, with Fernando Alonso in the upgraded Aston Martin splitting the two Ferrari cars.
Championship leader Max Verstappen was only sixth fastest in the lead Red Bull car and four tenths of a second off Hamilton's benchmark.
The Dutchman said: "We didn't have a good day and they had a good day. We know our limitations with the car - probably on a track like it is now with the bumps and kerbs - it definitely doesn't suit our package for now. We will try to find a few improvements."
Sky Sports F1's Karun Chandhok said: "Mercedes did their times later than other people, so they're slightly out of sync, but they're in amongst it with Ferrari, Aston Martin."
Sergio Perez was a two places further back in eighth, behind an impressive Valtteri Bottas, and had to abandon his first flying lap effort after a very close brush with the wall. The Mexican said upon arriving in Montreal that he needs perfect weekends for the remainder of the season as he seeks to reignite his title ambitions.
Sky Sports F1's David Croft added: "I just get the feeling Mercedes are in the hunt with Aston Martin, who probably don't understand perfectly the set up on their car as yet with the new upgrades.
"Ferrari are showing pace, and genuine pace over one lap. And for once, Verstappen and Perez are a bit off the pace."
After only four minutes of track action were possible in Practice One, the second session was also disrupted by two red flag periods.
First Nico Hulkenberg ground to a halt in a plume of smoke at the end of the pit straight after the engine in his Haas gave up.
And Esteban Ocon was then forced to stop on track with a water leak issue on his Alpine.
The drivers also had to contend with strong, gusty winds in the closing minutes of the session as rain storms arrived at the circuit.
Saturday's third practice session and qualifying are forecast to be run in the wet and a number of drivers did exploratory laps in the final minute on intermediate and wet tyres, with Bottas sliding on the grass at the hairpin where the rain was heaviest.