Lewis Hamilton was fastest but Felipe Massa's Williams managed to post the second quickest time in Saturday morning's final practice session ahead of qualifying for the Canadian Grand Prix.
Hamilton posted the best lap of one minute 15.610 seconds on the 4.361-kilomtre Circuit Gilles-Villeneuve but his Mercedes AMG teammate Nico Rosberg was caught for second place when Massa came in at 1:16.086 with all the drivers running on supersoft tires late in the one-hour session.
Rosberg was third at 1:16.120 while Fernando Alonso's Ferrari was at 1:16.488 and Daniel Ricciardo's Red Bull was fifth at 1:16.504.
The real test will come later Saturday in qualifying.
The Mercedes team has claimed all six pole positions and won all six races in Formula One this season. Massa has started no better than seventh on the grid and his best race finish was sixth.
Hamilton hit the curb hard on the final chicane before the home stretch and still bounced back with his quickest time. But the Briton returned to the garage for unspecified work on the car and, even when he returned to the track, he told his crew they needed to "sort out what was wrong."
The session stopped for four minutes early on after Esteban Gutierrez's Sauber spun out and needed to be lifted off the track.
The race is on Sunday.