Canadian GP: Nico Rosberg's Mercedes fastest between red flags

Teams had been hoping to gather crucial long-run data on the super-soft tyre after rain washed out more than half of second practice on Friday.

So drivers headed out onto the Montreal circuit early, with Ferrari's Sebastian Vettel and Kimi Raikkonen setting the opening pace.

But the action was halted for 10 minutes when Felipe Nasr crashed heavily on the long straight as he appeared to weave aggressively in a bid to generate tyre temperature.

The Brazilian climbed out of the Sauber unscathed, but was taken to the circuit medical centre as a precaution.

There was significant damage to the front end of the car, leaving Nasr's mechanics with a race against time to get the car ready for qualifying.

The session restarted with a little over 10 minutes remaining, with drivers bolting on the super-soft tyres to do a qualifying simulation.

But it was disrupted again when McLaren's Jenson Button stopped at Turn 7 to being out the second red flag of the session.

Rosberg was able to get a super-soft run in to go fastest, but his team-mate Lewis Hamilton was not so successful after making a mistake on his first lap.

The session was not restarted after Button's problem, which meant Rosberg's time of 1m15.660s was the quickest time of the morning while Hamilton propped up the timesheets having not managed a single clean flying lap between mistakes and stoppages.

With so many drivers unable to complete a super-soft tyre run, teams will have limited data going into qualifying.

Raikkonen was second quickest overall for Ferrari, ahead of Lotus's Romain Grosjean and the Williams of Valtteri Bottas.

Force India's Sergio Perez managed a super-soft run to end up fifth, with Red Bull's Daniil Kvyat sixth and Williams's Felipe Massa seventh.

Vettel, Carlos Sainz Jr and Pastor Maldonado completed the top 10.

Fernando Alonso managed just three laps after missing most of the session while McLaren fitted the fourth and final Honda engine of his allocation.

PRACTICE THREE TIMES: