Mercedes team principal Toto Wolff has criticised the Silver Arrows' current pace as unacceptable.
With F1 racing to a new set of aerodynamic regulations this season, Mercedes has found itself on the back foot and under threat of losing its grip on the constructors' championship title it has won for the last eight seasons.
The team has failed to win any of this term's seven races, its worst run since the end of 2013 before new power unit rules were introduced the following year.
The team's lack of pace in comparison to main rivals Red Bull and Ferrari has largely been down to the porpoising phenomenon associated with ground-effect cars, and in part exacerbated by its daring disappearing sidepod concept.
Upgrades on the W13s for the Spanish Grand Prix appeared to have significantly eased the problem for both Lewis Hamilton and George Russell but on the bumpy Monaco streets, the stiff chassis highlighted further bouncing issues.
Assessing Mercedes' chances in Azerbaijan this weekend, with the Baku City circuit another street course, Wolff explained: “The problem is we can say it is a track where it is going to be a little better, like in Barcelona, or a track that is worse like Monaco.
"I think we are the third [best] team - we are not second and we are not fourth.
“We have two extremely strong drivers but it is a huge annoyance for all of us that the gap is about the same.
“If you are looking at it optimistically it is five-tenths [of-a-second difference to the top-two teams]. If you are looking at it pessimistically it is more like eight-tenths.
“And clearly, for all of us at Mercedes, that is not acceptable.”