Lewis Hamilton described the Turkish Grand Prix track at Istanbul as "terrible" after his first qualifying flop of the year on Saturday as Racing Point's Lance Stroll, flourishing in the slippy conditions, secured a maiden career pole position.
Defending six-time champion Hamilton, who bids to capture a record-equalling seventh world title in Sunday's race, was only sixth in qualifying with his teammate Valtteri Bottas in ninth.
The Finn is the only driver who can stop the Briton taking the title again, if he can outscore him by eight points or more, but like Hamilton he struggled in treacherous rainswept and low-grip conditions.
"There isn't any grip at all," said Hamilton.
"I don't really know what to say. We did the best we could and that was the fastest we could go.
"The track feels terrible. It feels like driving on ice. For whatever reason, some people can get their tyres going, but ultimately, we're all struggling out there.
"I did the best I could and I didn't really make any mistakes so I'm generally happy. I did everything I could with what I had."
Asked by Sky Sports F1 if he was disappointed by his pace and form, after the prolonged red flag-interrupted session, Hamilton retorted: "Have you not been watching all weekend? I was 20th before this so this is an improvement."
Stroll's success in gaining his first pole, and Canada's first since Jacques Villeneuve at the 1997 European Grand Prix on his way to winning the title, ended Mercedes' run of 13 consecutive pole positions this season.
Stroll said it was "in my bones" to shine in severe wet and treacherous conditions after delivering the greatest moment of his career.
- 'It's in my bones' -
The 22-year-old Canadian, whose billionaire father Laurence Stroll is owner of the Racing Point team, outpaced the sport's big names in the final seconds of a prolonged and dramatic session.
He said he owed his success to feeling at home in the slippery and treacherous conditions as heavy rain interrupted proceedings and rendered the track unsafe for 45 minutes.
"I love it and I have always enjoyed it," said Stroll.
"At home, I grew up driving on ice in our parking lot with lots of drifting and sliding around without much grip. It's in my bones."
He added: "There were a lot of things we weren't sure about coming into qualifying. We didn't look that competitive in Q3. I'm so happy right now -- I put that lap together at the end when I was under a lot of pressure."
Max Verstappen in a Red Bull will start second on the grid ahead of Sergio Perez in the other Racing Point and Alex Albon in the second Red Bull.
Renault's Daniel Ricciardo was fifth fastest and shares the third row with Hamilton.
Stroll had a nervous conclusion to Saturday, however, when he was placed under a stewards investigation for allegedly ignoring yellow flags.
He was eventually cleared of any wrongdoing after a Turn Seven incident which had seen Perez go off.
McLaren's Carlos Sainz was handed a three-place grid penalty for impeding Perez as he left the pits.
Teammate Lando Norris was then demoted five places for ignoring yellow flags.
The penalties are a setback for McLaren as they battle Renault and Racing Point to secure third place in the constructors championship.
The three teams are separated by only one point with four races remaining.
Sainz, who was 13th, said the stewards could have been more considerate of the difficulties caused by the severe low-grip wet and cold conditions at the Istanbul Park Circuit.
"We're all trying to warm up our tyres and I think the stewards need to consider that," he said.
"And we are all struggling to stay on the track."