Lewis Hamilton will start the 2018 Canadian Grand Prix from the second row of the grid tomorrow. Fourth place is his worst grid position in Montreal since 2011.
Meanwhile his chief rival for the championship, Ferrari's Sebastian Vettel, will be on pole.
A clearly disappointed Hamilton admitted that he had his work cut out for him overnight if he was to find the sort of pace that usually makes him unbeatable around the Circuit Gilles Villeneuve, having won the last three races in a row.
"It was a difficult qualifying. My laps weren't good and it just didn't quite come together for me," he said.
"It didn't really develop, it didn't get much quicker and it was just a difficult session," he signed. "Just weren't good laps.
"In practice things looked good and I think I could have been quickest in FP3," he suggested. "But in qualifying I couldn't quite hit the potential we had shown."
Mercedes had come into the weekend on the back foot after being forced to postpone their planned power unit upgrade. That was due to a reliability issue on the new upgrades that had been detected back in Brackley during the week.
It means Hamilton is using an engine that has already completed six full races, while the majority of his rivals are are fresh units. But the Briton insisted that this hadn't been an issue in his poor qualifying performance.
"I don't think today's performance has got anything to do with the older engine," he said. "Sebastian simply did a better job when it counted in Q3.
"You can see just how tight things are at the front of the grid," he added. "Just today it didn't come together. I don't think it was anything to do with the engine."
Hamilton appeared doubtful about whether he would be able to challenge the cars ahead of him on the grid in tomorrow's race.
"Our race pace was quite good yesterday. I think our single lap pace looked quite good as well," he said. "[But] I think it could be tricky to overtake tomorrow.
"I haven't really looked into it to be honest. I think it was all quite close between us but they did a better job today, and that's the way it is.
"Sure, it'll be tough to win from fourth here, but nothing is impossible. I'll dig deep tonight. My focus now is on tomorrow."
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