Montreal FP3: Rosberg first, Hamilton last

Nico Rosberg topped the timesheets while world champion Mercedes team mate Lewis Hamilton propped them up in Saturday's final Canadian Grand Prix practice.

Hamilton, who will be chasing his sixth pole position in seven Formula One races this season, failed to get in a clean lap in a scrappy session twice red-flagged due to incidents.

Rosberg's best lap of one minute 15.660 seconds was 0.573 quicker than Ferrari's Kimi Raikkonen in second place.

Hamilton, who ended Friday's rainswept second practice session in the tyre wall but fastest, was slowest of all with an unrepresentative time of 1:21.492 after managing just nine laps in all.

The Briton leads Rosberg by 10 points, arriving in Canada determined to bounce back from disappointment in Monaco where a needless late pitstop while leading cost him victory and handed it to his team mate.

After Friday's washout, the Saturday session started under clear blue skies but the drivers were still hampered by interruptions.

The first red flag came out when Brazilian Felipe Nasr's Sauber speared into the wall as he was weaving on the straight to heat up the tyres.

After a 10 minute suspension, with Nasr taken to the medical centre for checks and the wreckage removed, the action resumed but was again halted when Jenson Button's McLaren stopped on track and had to be recovered.

"I had a massive loss of power. We've got a bigger problem here," Button said over the radio, with his participation in qualifying in doubt.

Button's Spanish team mate Fernando Alonso managed only three laps after sitting out most of the morning as mechanics installed a new Honda power unit.

[highlight ]Canadian Grand Prix, Free Practice 3 - Saturday, 6 June 2015[/highlight]