Nico Rosberg set the pace in the final practice session ahead of qualifying in what proved to be a costly morning in Canada for Toro Rosso.
The session begun under blue skies with the weather forecast claiming it should stay that way throughout the morning, although rain could fall some time in the afternoon.
The Force India cars of Adrian Sutil and Giancarlo Fisichella were the first out on track for their morning installation laps. They were quickly followed by a train of 11 other cars.
After ten minutes only the two Ferraris and Honda had yet to make an appearance while none of the other drivers had to venture out for a second lap or set a time.
Nick Heidfeld, who found traffic in the form of Sebastian Vettel in Turn Five, finally set the first time of the morning, a 1:19.344.
Sutil and Seb Bourdais also made their mark while the Ferrari of Kimi Raikkonen made his way out for his first run of the morning. The Finn went P3 but improved enough on the following lap to take the top spot off Heidfeld. Robert Kubica went third ahead of Fisichella, Vettel and Jenson Button.
Bourdais improved to second place before losing out to Fisichella and then Kubica. The Pole then made the move up to P1 while Heikki Kovalainen went third behind Raikkonen. Lewis Hamilton went fifth on his first timed lap, slotting in behind Nico Rosberg and ahead of Felipe Massa.
Rosberg was the next to hit the P1 position, clocking a 1:17.297, before he was overhauled by Raikkonen, the first driver to break into the 1:16s. Rosberg, though, fought back, returning to the top. Massa improved to third place.
Kovalainen took third place off Massa, who was relegated another position by Hamilton bettering his McLaren team-mate's time. The Brazilian, though, came back to slot in between the two McLarens.
With 15 minutes remaining Vettel became the first casualty of the session when the Toro Rosso driver lost control of the back end of his STR3, crashing heavily into the concrete wall at Turn 9. The German climbed unaided from his car however due to where it came to a rest the session had to be red-flagged so that the marshals could clear away the car and the debris left behind on the track.
Play resumed with six minutes on the clock, just enough time for all the drivers, barring Vettel, to put in their final few laps before qualifying, many opting for the softer option Bridgestone tyres.
However, it turned out to be a bad option for Toro Rosso, who lost their second car, Bourdais after he hit the concrete wall at Turn Five damaging his STR3.
The session therefore ended with Rosberg quickest, ahead of Raikkonen, Hamilton, Massa, Kazuki Nakajima and Jarno Trulli. Kovalainen and Nelson Piquet Jr completed the top eight.
Returning to the pits Piquet Jr lost control of his Renault, lightly tapping the wall before coming to a stop.
Times
01 N. Rosberg Williams 1:16.555 16 laps
02 K. Räikkönen Ferrari 1:16.589 22 laps
03 L. Hamilton McLaren 1:16.725 17 laps
04 F. Massa Ferrari 1:16.787 19 laps
05 K. Nakajima Williams 1:16.898 16 laps
06 J. Trulli Toyota 1:16.946 20 laps
07 H. Kovalainen McLaren 1:16.952 16 laps
08 N. Piquet jr. Renault 1:17.060 19 laps
09 M. Webber Red Bull 1:17.062 16 laps
10 S. Vettel Scuderia Toro Rosso 1:17.085 16 laps
11 R. Kubica BMW 1:17.109 17 laps
12 S. Bourdais Scuderia Toro Rosso 1:17.282 17 laps
13 D. Coulthard Red Bull 1:17.322 20 laps
14 R. Barrichello Honda 1:17.557 19 laps
15 T. Glock Toyota 1:17.557 20 laps
16 G. Fisichella Force India F1 1:17.608 24 laps
17 F. Alonso Renault 1:17.683 16 laps
18 N. Heidfeld BMW 1:17.766 17 laps
19 J. Button Honda 1:18.178 19 laps
20 A. Sutil Force India F1 1:18.424 21 laps
