Mercedes F1 boss Toto Wolff says the reigning world champions must prove their "ability to react" next weekend in Bahrain following the team's troubled pre-season preparations.
Reliability issues on the first day of testing coupled with handling problems that impacted its W12 at Sakhir left Mercedes' crews scrambling for solutions to improve the rear-end stability of its 2021 car in time for this week's season opening round.
"It feels like we have spent quite some time in Bahrain recently, and with mixed fortunes," said Wolff in the Brackley sqaud's Bahrain GP preview.
"Overall, it was a tricky three days of testing for us. The W12 wasn't as stable, predictable or planted as some of our rivals. Red Bull looked strong on both the long and the short runs, but as always with testing, it's difficult to be certain of true performance."
"The only thing we know for sure is that we must prove our ability to react. From the moment the third day of testing finished, we got our heads down and started to figure out how we can return to Bahrain in stronger form in just a few days' time."
©Mercedes
The teams' 2021 contenders are based on last year's chassis as mandated by the regulations, although several aerodynamic rule changes have been implemented on the new designs.
Wolff believes the modifications have been more significant than anticipated and a challenge to carry out. But ultimately the Austrian is confident that Mercedes' troops will fight back to hold their own at the head of the pack.
"While these cars share some parts from their predecessors, there have also been significant rule changes to interpret and overcome," said Wolff.
"We have also had to change the way we work in response to the cost cap. But as we have found before, it's from the difficult moments that we learn the most.
"This team's biggest strengths are our people and our values, and after a tough test, I know that we can fight back stronger.
"I'm looking forward to getting this new and exciting season underway, seeing the progress we can make and how we fare in Bahrain."
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