Lewis Hamilton faced a nervous wait to see if he would start the Canadian Grand Prix from second place after Mercedes discovered a problem with his car.
Hamilton's team found an hydraulic leak late on Saturday afternoon and were attempting to fix the issue with a little more than two hours to go before the start of the race in Montreal.
The world champion was due to start behind Ferrari's Sebastian Vettel, who secured his first pole position in 17 grands prix at the Circuit Gilles Villeneuve on Saturday.
Mercedes were hopeful Hamilton's car would be ready in time, but the championship leader would have to start from the pit lane if they were unable to get his machine up and running.
Hamilton headed into the seventh round of the championship with a 17-point lead over team-mate Valtteri Bottas.
Vettel, bidding to end a 287-day winless streak, was 55 points behind the Briton.
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