Mercedes did not have the smoothest three days of testing at the Sakhir International Circuit.  

A gearbox change on the opening morning restricted Valtteri Bottas to just six laps as early problems struck the seven-time defending World Champions. Lewis Hamilton also had issues as he spun into the gravel during day two; the rear of the Mercedes seemed far from settled throughout the test. 

They bolted on a set of C5s (the softest compound available) in the closing stages of the final day but Hamilton could only manage to go P5, almost 1.1s off the quickest time set by Red Bull’s Max Verstappen. 

While Mercedes has a history of sandbagging in pre-season testing and downplaying their performance, trackside engineering director Andrew Shovlin says Red Bull is faster and they’ve work to do to extract more from the car when they return to Bahrain for FP1 in 12 days. 

"We've made a bit of progress with the balance on higher fuel and the car was more predictable but we can see from the data we've collected over the last few days that on race pace, we're not as quick as Red Bull," Shovlin said according to Motorsport.com. 

"The lower fuel work was a more confusing picture; we didn't gain enough and we need to go and look at our approach as far too many cars were ahead of us on pace today. 

"We've had issues in recent years with pace in winter testing and managed to make good progress before the first race but we may have our work cut out this time. 

"We've not got long before we're back here for the race so we've planned a programme of work to try and understand some of our issues and will be leaving no stone unturned in our efforts to find some more speed over the next 10 days." 

Lewis Hamilton and Valtteri Bottas echoed Shovelin’s sentiments as they look to find the sweet spot with the W12.  

"Today we made some improvements but it's still not where we want to be," Hamilton said. 

"I can't pick out any one area, it just feels globally through the lap that we need to improve. I'm looking forward to getting back into competition and back in that focus mode." 

“I absolutely believe the car and the team, it has the potential [to take the title],” said Bottas. “I don’t think it’s yet there as a package in terms of performance, but I’ve no doubt that we will work hard to find it somehow. 

“I’m still not fully comfortable. We’ve been going forwards, I think, with the set-up of the car and understanding of the car, and getting it to behave better, but still there is more work to do, and from these busy few days, there’s lots of data that hopefully can help us to make the car faster when we race here.”