Red Bull driver Mark Webber of Australia steers his car during the third free practice at the Gilles Villeneuve racetrack, in Montreal, Canada. (AP)
Mark Webber took advantage of late drying conditions to clock the fastest time for Red Bull in Saturday's delayed and truncated final free practice session for Sunday's Canadian Grand Prix.
The 36-year-old Australian was the last man out at the right time and lapped in one minute and 17.895 seconds to outpace Adrian Sutil of Force India by three-tenths of a second.
Lewis Hamilton of Mercedes was third fastest ahead of Fernando Alonso of Ferrari, defending triple world champion Sebastian Vettel of Red Bull and sixth-placed Nico Rosberg in the second Mercedes.
Paul Di Resta in the second Force India was seventh, Felipe Massa of Ferrari eighth and Jenson Button of McLaren ninth with Kimi Raikkonen 10th for Lotus.
The final times were almost meaningless, however, because they were all produced in the closing four minutes of a session reduced to 30 minutes because of an earlier delay to repair barriers at the Circuit Gilles Villeneuve.
In the drying, rapidly-improving conditions, it was clear that the times were tumbling after a spate of minor off-track excursions earlier when the circuit was more slippery. There were, however, no serious accidents.
On a cold morning following more rain, an accident involving a support race car that had damaged the steel barriers around the circuit caused the 30-minutes delay for the third and final free practice session and reduced its duration from an hour to just half an hour.
The track temperature was only 14 degrees Celsius and this meant, also, that it was difficult for all of the teams and drivers to generate the necessary heat in their tyres for a decent level of speed and grip.
When the temperature crept up and the track surface dried out, the teams risked running on soft tyres in the final minutes and in the circumstances it was effectively a lottery as to who would be running last when the chequered flag came out.