REUTERS: Lewis Hamilton hailed a monumental turnaround by his Mercedes Formula One team on Saturday after overcoming problems in practice to secure a front row starting position at the Azerbaijan Grand Prix.
The seven-times world champion was only 11th in Friday's second practice, and more than a second off the pace set by Red Bull.
He had ended the opening day in Baku with more questions than answers, but a crash-hit qualifying session changed everything.
Hamilton qualified second behind surprise Ferrari pole-sitter Charles Leclerc, with Red Bull's championship leader Max Verstappen third.
"We definitely weren't expecting that," said the 36-year-old Briton, who is four points behind Verstappen after five races.
"This is such a monumental result for us because we've been struggling like you couldn't believe all weekend.
"We kept our composure... We've moved around, made so many changes over these two days, just chasing our tail and it's been so difficult."
Hamilton said it was "one of the greatest feelings" to be back in the game, overwhelming even - quite a statement from the most successful driver in the history of the sport - and the jump was the biggest by the team from one day to another.
Winner of three races this season, Hamilton said the Mercedes felt "really terrible to drive" in practice and the change was like 'night and day' as they got the tyres to perform.
"Trying to find the (performance) envelope for this car... it's like the biggest challenge we've had in a long time trying to understand what the car really wants.
"She's not been happy all weekend, it's been a bit of a disaster, so for us to be up here, and even Valtteri (Bottas) getting into the top 10, that's a massive leap," added the champion.
Mercedes have won the last two races in Baku, in 2018 and 2019, and Hamilton said the race pace this season has been a lot better than over a single lap.
"We don't know why but I'd like to think hopefully we're in that same position so we can take the fight to these guys tomorrow," he said, adding that Sunday now looked a different race to the one expected.
Mercedes team boss Toto Wolff denied the pace disparity between his drivers, with Bottas qualifying 10th, was down to different rear wing settings.
"The difference was that the car was very tricky all weekend and somehow Lewis found the confidence for qualifying and Valtteri struggled," said the Austrian.
(Reporting by Alan Baldwin in London, editing by Pritha Sarkar)