Lewis Hamilton topped the opening practice session for the Canadian Grand Prix on Friday, meanwhile Williams' Felipe Massa crashed heavily at Turn 1, bringing out the red flag.
Hamilton posted a 1m14.755s lap to top the timing screens in the morning for Mercedes, beating team-mate Nico Rosberg by more than three-tenths.
Sebastian Vettel was third quickest for Ferrari, using their upgraded turbo, to finish almost half a second down around the Circuit Gilles Villeneuve.
During the session, Massa lost control of his car as he headed down the start/finish straight, spinning out and heading into the barrier backwards, heavily damaging his car. The Brazilian blamed DRS for the incident, which brought out the red flag.
With the accident cleared, Rosberg was quickest whilst Hamilton – a four-time winner here – cut the chicane on his fastest lap, which meant it was deleted, before finally dipping below the 1m14s barrier on his next attempt.
Max Verstappen split the Mercedes, but eventually wound up fourth quickest, whilst team-mate Daniel Ricciardo could only manage P11, behind McLaren's Fernando Alonso.
McLaren didn't enjoy the smoothest of sessions, with a hydraulic problem hitting Alonso, before Jenson Button suffered an oil leak. He managed to rejoin the action in a cloud of smoke as he exited his garage.
