MONACO (AP) While resurgent Ferrari keeps improving, Mercedes is at a loss to explain the difference in performance between its two cars.
Ferrari will start the Monaco Grand Prix on Sunday with Kimi Raikkonen in pole position and championship leader Sebastian Vettel next to him.
Although Valtteri Bottas qualified in third place, his Mercedes teammate Lewis Hamilton was out of the top 10.
''We have to try and understand what's happening, how we are going backward over the weekend,'' Mercedes head of motorsport Toto Wolff said. ''There is a certain DNA in the car. It seems to be a bit of a diva.''
Ferrari has been quick all week, setting lap records in Monaco while Mercedes - so invincible-looking for the previous three years - struggled from the second practice onward. Although Mercedes sorted out Bottas' car for qualifying, Hamilton's car continued to be dogged by tire and balance problems, and he could set only the 14th best time.
''I was devastated after the session, to the point where I couldn't get out of the car. So much energy and work goes into these weeks,'' Hamilton said. ''When you see the other car is able to work, you can't think for the life of you why you weren't able to. It feels like a mystery.''
Last year, Ferrari was doing the head-scratching, but Raikkonen's and Vettel's cars both look in great shape now.
''I was very happy with the car,'' Raikkonen, the 2007 F1 champion, said with typically minimal fuss. ''Nice, straightforward qualifying.''
Raikkonen's last pole was in 2008 at the French GP, but the Finnish driver coasted to this one. Pole is even more valuable at Monaco, the hardest track to overtake on in F1.
Given the reliability and speed of Ferrari's car, Raikkonen has a good chance of securing a 21st race win and his first since 2013 when he drove for Lotus at the season-opening Australian GP.
Raikkonen is fourth in the championship but 55 points behind Vettel. He dismissed any talk that he might receive team orders in order to make way for Vettel, who has 44 career wins.
''I don't know why everyone thinks it will be different tomorrow than the last two years,'' Raikkonen said. ''Just trying to make a stupid story or something. It's going to be a long, difficult race.''
Even more so for Hamilton, whose chances of a third win at Monaco and 56th overall look bleak.
He headed into the weekend six points behind Vettel and aiming to move level with Ayrton Senna's total of 65 pole positions. Instead, he will probably be scrapping for small points.
''Tomorrow's race will clearly be a case of damage limitation for him,'' Wolff said.
The warning signs were there as early as Thursday, when the team botched a switch to quicker ultra-soft tires and Hamilton placed eighth in the second practice. While Vettel and Raikkonen took 1-2 in the final practice on Saturday, he was only fifth.
Then, in qualifying, he went backwards.
Verstappen was fastest in Q1 and Hamilton an ominous 10th.
Hamilton had a near miss early in Q2 when his car wobbled at the Massenet turn and he complained of a lack of grip. Mercedes took him back into the garage for a tire change but he still struggled with the car's balance.
McLaren's Stoffel Vandoorne crashed near the end of Q2, meaning a yellow flag ended it about one minute early. But Hamilton was arguably too far behind to reach the top 10 shootout.
''It doesn't really matter,'' Hamilton said. ''I would have struggled to make it into the top five with the pace that I had.''