Mercedes technical director James Allison has revealed there were "lots of sleepless nights" as Mercedes attempted to find a fix for the gearbox sensor issues suffered during the Austrian Grand Prix.
During the early stages of the season opener, Valtteri Bottas and Lewis Hamilton were warned to stay clear of the kerbs as "critical" damage was being caused to the cars.
Knowing they would again be racing at the Red Bull Ring the week after, Mercedes sprung into action to find a fix.
Speaking in a Mercedes video, Allison said: "It was a big scary thing, lots and lots of people involved, and lots of sleepless nights."
Explaining how close to retirement the cars of Lewis Hamilton and race winner Valtteri Bottas had come, Allison explained: "The sensor issue we had in the first Austrian race was a really scary one. We finished that weekend hanging on by the very tips of our fingernails. It was not a comfortable experience at all.
"It wasn't comfortable because we knew on the Friday we were in deep trouble, and so, from that Friday of the first Austrian race, there was already an awful lot of work going on back at the factory to try to understand what it was that was letting us down at the front end of the gearbox."
He explained: "It was an awful lot of work with both the electronic designers, with the people that are then able to do rig testing and gearboxes so that we could run at the factory to make sure that it worked, and for the people that had to manufacture the new looms and the new cable boots and connector boots, so we could get them back to the track.
"That work started on the Friday of the first Austria [race], the design was completed midway through Monday, we were making bits on the Tuesday, we delivered them by the Wednesday, and we were testing them on Thursday so we could just stay a small whisker ahead of the track running for the second Austria."