Red Bull's Sebastian Vettel set the pace in final practice at the Canadian Grand Prix ahead of qualifying on Saturday.
The world champion was 0.320 seconds quicker than Ferrari's Fernando Alonso, with Mercedes' Nico Rosberg third ahead of Alonso's team-mate Felipe Massa.
The McLarens of Jenson Button and Lewis Hamilton were fifth and sixth.
Sauber's Pedro la Rosa became the fifth driver this weekend to crash at one of the track's challenging chicanes.
The Spaniard has been drafted in to replace Mexican Sergio Perez, who withdrew after first practice on Friday feeling ill effects from his crash in Monaco Grand Prix qualifying two weeks previously, in which he suffered concussion.
De la Rosa lost the rear of the car coming through the chicane at Turns Three and Four. He ended the session 17th fastest, slightly less than half a second slower than team-mate Kamui Kobayashi, who was 15th.
Among the leading runners, Mark Webber, who was off the pace of team-mate Sebastian Vettel on Friday, was unable to do any running at all because of a battery problem with his Kers system.
The car spent the session in pieces in the Red Bull garage. BBC F1 pit-lane reporter Jennie Gow said: "I can't count the number of pieces Mark Webber's car is in - there are bits everywhere, it's probably four pieces.
"A couple of guys are working furiously at the back of the car, everyone else to be honest seems to be having a chat and there is no great sense of urgency. Whatever the problem only two people seem to be able to fix it and Webber is nowhere to be seen."
A number of drivers ran wide at the chicanes as they explored the limits of their cars, including Hamilton.
But until De la Rosa's crash, none had repeated the antics of Friday, when Vettel, Force India's Adrian Sutil, Kobayashi and Virgin's Jerome D'Ambrosio all crashed.
Michael Schumacher was seventh fastest, 0.5secs off the pace of team-mate Rosberg, who set his time early in the session the super-soft tyres, whereas most drivers saved them until the end.
Alonso set his best time towards the end of a multi-lap run on the super-soft tyre, whereas Vettel did his much earlier.
McLaren's apparent lack of pace was something of a surprise after Hamilton had set lap times comparable to Vettel's on a long run on Friday.
The session ended under increasingly grey skies, and rain is forecast for some time during the afternoon.