Jenson Button is hopeful that the gearbox problem that he struggled with in Friday's practice won't prove costly during the race on Sunday.
The McLaren driver's planned long run was cut short when a gearbox problem brought an early end to his day, leaving the team short on data ahead of qualifying.
"I think the pace today was OK, we were running different downforce levels in the second session which was interesting, it's just whether we're brave enough to attempt something like that with having only done a couple of laps on high fuel loads," Button said.
"The long-run information is really what I needed on my car, so it's going to be difficult to know what to do with the balance and set-up for tomorrow."
The former World Champion added that the short run during the only dry session of the day ruined the team's development programme for the race.
"We were trying something in that session which was quite interesting but we didn't get the information while running on high fuel," the Briton continued.
"I did three laps. It's very difficult to go into a race and you'd be very brave to put that part on the car, if you've only done three laps on it."
Button also admitted that he fears a repeat of last year's race, when then team-mate Lewis Hamilton lapped him after he struggled with tyre performance and grip around the Gilles Villeneuve Circuit.
"We had that issue last year when we had a gearbox problem and had a disastrous race because of rear graining," he added.
"We needed to be reliable today, but we're running different set-ups on both cars so at least we got some information."