Mercedes technical director James Allison believes tyres were the key factor as to why the team were off the pace at the Monaco GP.
Lewis Hamilton had one of his worst qualifying performances of his Formula 1 career, qualifying in seventh place and was unable to make any progress in the race.
"We need to figure out why we were slow. It's the slowness that is the main pain," Allison told RacingNews365.com and other select members of the press.
"Ironically our car, which one of its best weapons has been its tyre usage on various tracks, on this particular track we always struggle a bit with tyre usage. We're never really getting them happy on a Saturday so our grid slots are lowly.
"Then on Sunday, although we're okay at the start of the stints, by the end of the first stint where most of the crucial action takes place at this particular track, we were normally all out of ideas with a tyre that dies a little sooner than our competitors.
"It's understanding that, that we've failed to do for a number of seasons and we need to figure out from first principles, 'what are we getting wrong at this track?'"
Valtteri Bottas fared better and qualified in third place, just 0.025 seconds slower than Max Verstappen. Allison feels that Bottas did a better job than Hamilton in terms of finding the optimal working window at Monaco.
"Valtteri was able to get the front tires happier at the beginning of the lap. Then for the rest of the lap he had more confidence to welly into the lap and take the car near the barriers which is what you need to do to get a good qualifying lap
"Objectively just a bit of difference in the temperature between the front tyres on the two cars. But both drivers are basically suffering with the front tyres coming in later than the rear tyres, coming into their best window that is."