Toto Wolff says Mercedes have not been able to get their Formula 1 car in the set-up "sweet spot" since the Australian Grand Prix.
Mercedes have struggled with their W14 car concept, admitting in Bahrain that the zero sidepod approach was wrong and committed to an effective B-spec of the car, although this was already in development before Wolff announced the change after Qualifying in Sakhir.
They were due to bring the huge upgrade to Imola for the Emilia Romagna Grand Prix, but with that race's cancellation, it is likely to now wait until the Spanish Grand Prix in two weeks rather than Monaco next time out.
In Australia, George Russell and Lewis Hamilton qualified second and third with Hamilton finishing in second in their best showing of the year, while in Azerbaijan and Miami, both Ferrari and Aston Martin have looked the main opposition to Red Bull.
And Wolff says the team have yet to replicate the "sweet spot" they found in Melbourne.
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Mercedes in "sweet spot"
"Melbourne is a very front limited track, we put the car in a sweet spot and it was performing very well," Wolff told media including RacingNews365.
"It got better over the weekend, and it is the country of what happened [in Miami] as it got worse over the weekend.
"It is so narrow that a good weekend on the current car [we are ok] but there is no pleasure in a sixth place when the car is so bad.
"There is such a narrow operating window that when [the car] is good, it is okay, and it can deliver a podium.
"If it is bad, you'll searching for P10 realistically in terms of things.
"A good car is a car that the drivers are able to push and feel that it doesn't do anything unpredictable.
"And unfortunately, we've had that over the last year and this year, particularly in qualifying where you really need to push the limits, the drivers couldn't find any confidence in the car."
Balve Bains is joined by RacingNews365.com Editorial Director Dieter Rencken and Asia Correspondent Michael Butterworth to ask if Mattia Binotto could really join Alpine, what Pirelli's new tyres are about and the latest on the Red Bull-Ford partnership!