Toto Wolff is unsure whether Mercedes can recover challenge for an F1 championship next season after a difficult first campaign in the sport's new regulatory era.
The Silver Arrows slumped to its worst championship standing since 2012 after finishing third to Red Bull and Ferrari.
The season also brought to an end a previously perfect record for Lewis Hamilton with at least one win and one pole position in each year of his career.
Although George Russell's victory at the Brazilian Grand Prix and strong late performances in Mexico and the United States raised spirits within the team, these instances did nothing to distract from the overall disappointing picture.
Asked if he was confident that Mercedes has the ability to return as a title contender next year, team principal Wolff conceded: "[I'm] never confident.
"I'm a glass-half-empty guy, never believing the job we are doing is good enough.
"I'm not sure at all whether we can bounce back to a position where we can compete for a championship.
"You need to acknowledge the competition is strong, but we will do everything in our power - everything - to set our objectives high and try to reach them."