Nico Rosberg emerged on top of the timesheets at the end of the opening 90 minutes of free practice at the Circuit Gilles Villeneuve in Montreal, as F1 began preparations for its mid-season transatlantic sojourn.
The German pushed his Mercedes to a time of 1min 15.591secs, enjoying an advantage of more than half a second of nearest rival, Fernando Alonso, but the headlines were again to be shared with fellow German Sebastian Vettel, who ended his session prematurely, and fittingly, in the Wall of Champions that lines the final chicane.
The session was red-flagged for around ten minutes to allow for the safe removal of Vettel's #1 machine, which locked up under protest entering the chicane and spat the world champion off into the outside wall, badly damaging its right front corner in the process. Resuming with just under 30 minutes remaining, the action continued, with Alonso taking over from Ferrari team-mate Felipe Massa at the top of the times, before Rosberg responded with his own improvement with just over ten minutes left on the clock.
The German's time would stand to the end of the session, despite the best efforts of several other drivers, but Rosberg reported shortly before the chequered flag that he felt a burning sensation inside the cockpit, and appeared hot and bothered as he climbed from the car. The Mercedes has struggled with cooling problems this season, but it is not known if the problem was linked to the team's ongoing battle with ventilation.
Alonso ended the session sandwiched between the two Mercedes, as Michael Schumacher - the most successful driver in the history of the Ile Notre Dame circuit - also surpassed Massa's best to move into third place, with McLaren duo Jenson Button and Lewis Hamilton 'best of the rest' in fifth and sixth, despite the latter seeing his car up on stands and being taken apart midway through the session. Like Massa, both McLarens were over a second off the pace, while Rubens Barrichello, rookie Paul di Resta, Nick Heidfeld and Nico Hulkenberg completed an unusual top ten, ahead of the returning Sergio Perez.
The best of the Red Bulls was only twelfth, in the hands of Mark Webber, fully 2.2secs off Rosberg's best effort, but, with Pirelli introducing a new hard compound tyre to complement its familiar 'soft' during the session, comparing times was no easy matter. Behind Webber, Jaime Alguersuari survived a big slide over the chicane at Turn Eight to claim 13th spot, two places ahead of impressive Toro Rosso reserve Daniel Ricciardo, and a late-starting Vitaly Petrov between them. Vettel, meanwhile, could only manage 16th based on eight completed laps.
Pastor Maldonado was next up on his first visit to the track, with both Lotus drivers getting ahead of the second Sauber of Kamui Kobayashi and Tonio Liuzzi getting the better of Virgin's Timo Glock.