Fernando Alonso showed signs of progress by Ferrari with its power unit as he topped Friday's opening practice session of the Canadian Grand Prix, ahead of Mercedes pair Lewis Hamilton and Nico Rosberg.
Alonso's benchmark of 1:17.238 pipped Hamilton by 0.02s, who was a tenth quicker than team-mate Rosberg. Though it is unlikely Mercedes played its full hand the pace shown by Alonso will be an encouragement for Ferrari after bringing significant engine and aerodynamic upgrades for Montreal.
Ferrari's joy may be tempered by problems encountered by Kimi Raikkonen early on in the session, after the Finn complained of a loss of power through the straights, which the team explained was due to engine knock. The issue appeared to hamper Raikkonen's progress in the opening stages and he only completed 15 laps in the session.
Red Bull once again led the charge for the Renault teams with Sebastian Vettel finishing fourth, albeit a full eight tenths off the pace of nearest man Rosberg, with Daniel Ricciardo slotting into sixth behind Valtteri Bottas' Williams.
A lack of grip was an issue early on, with Sebastian Vettel among the drivers going straight on at the final chicane in the opening stages. Lewis Hamilton locked up and went straight across at Turn 1 after his first timed run in the opening half hour as the drivers struggled to warm up the tyres in the cooler temperatures.
Following his historic points finish in Monaco, Jules Bianchi came back to earth with a bang after bouncing both tyres of his Marussia off the wall at Turn 4. He managed to go get the car going again but it was soon apparent the right rear corner of his car was damaged and, though Bianchi was able to hobble back to the pits, his session was over.
Felipe Massa was another whose session came to an abrupt end, as a ERS issue meant his car spent the final half hour being dismantled in the Williams garage. Esteban Gutierrez's track time was also limited as his Sauber hit problems, while Jean-Eric Vergne's session was cut short due to a battery issue.
In the closing stages the team's set about doing their longer runs on the prime tyre, with Pastor Maldonado continuing Lotus' habit of accumulating the most mileage in the opening session by completing 37 laps.