The 2013 Formula 1 Canadian Grand Prix got off to a wet and cold start on Friday afternoon, with heavy rain before the first practice session limiting track time.
Eventually though, Force India's Paul di Resta finished on top of the timesheets. The British driver posted 1:21.020 late in the 90-minute session to pip compatriot Jenson Button and McLaren. Lotus-Renault's Romain Grosjean finished third with 1:21.528.
Ferrari's Fernando Alonso was fourth with 1:21.308 and Grosjean's team mate, Kimi Raikkonen, closed out the top five with 1:21.608.
UPDATE: Sebastian Vettel claims pole position at 2013 Canadian Grand Prix, with Mercedes' Lewis Hamilton and Williams' Valtteri Bottas second and third.
There was standing water at several points on the Circuit Gilles Villeneuve at the start of the session. Weather conditions forced teams to play the waiting game for the first 15-odd minutes of the session. Sauber driver Esteban Guttierez and Marussia's Max Chilton were first out on track but both drivers went back in after installation laps. Red Bull drivers Sebastian Vettel and Mark Webber also made brief appearances but neither set a time.
Gutierrez posted the first time of the session - 1:34.113. He quickly improved to 1:30.224, after the team reported a change in the weather. That set the ball rolling, with Webber posting 1:29.412 on intermediate tyres and followed that with 1:27.909.
The first signs of a clear racing line emerged after approximately 30 minutes and the Monaco Grand Prix winner Nico Rosberg responded by producing the fastest time of the session.
The Mercedes team continue to be embroiled in controversy after news of a potentially illegal in-season test with Pirelli, using a 2013-spec car. The FIA have called the German side to appear before the International Tribunal.
Pirelli, meanwhile, will be a little disappointed that the experimental medium compound tyre they brought to this race weekend did not see the expected amount of running. It is understood the Italians hope to have solved the delamination problem the rear tyres face this so far this season.
Meanwhile, back on track, although there was a dry line emerging, the street-circuit nature of the Circuit Gilles Villeneuve and inconsistent drainage facilities meant the track was still a little slippery and Rosberg's team mate, Lewis Hamilton, illustrated that with problems going over the kerbs for the final chicane.
With 30 minutes to go Rosberg improved to 1:23.680 for first place and six minutes later Toro Rosso's Jean-Eric Vergne was the first driver to try the new Pirelli medium compounds. However, the move to racing tyres was premature; the Frenchman reported the track was still too wet.
But with 15 minutes on the clock, a number of front runners opted to try and set fast times. Alonso and his Ferrari team mate, Felipe Massa, were joined by Vettel and Raikkonen and in a chaotic final few minutes, di Resta claimed top place.
Vettel was left down in ninth with 1:23.047; Webber was 10th with 0.084s gap. Rosberg may have led the session at one point but eventually had to settle for seventh, behind the Toro Rosso of Daniel Ricciardo.
For the full timesheet of the first practice session, click here.