Mercedes need more to match Ferrari - Bottas
Valtteri Bottas feels Mercedes have more work to do if they are to compete with Ferrari in the first part of the new Formula One season.
The teams are currently engaging in pre-season testing, with Ferrari setting the pace early on, despite a mechanical issue that led to Sebastian Vettel's crash in Barcelona on Wednesday.
And while Mercedes driver Bottas has been encouraged by steady improvement in recent weeks, he still thinks the Silver Arrows can get more out of the car before the season starts in Australia next month.
"It is better. But if it's enough, that is the big question mark," he told reporters of the vehicle.
"I definitely feel improvements since last week with the stability of the car and with the overall downforce of the car, but we definitely feel that we haven't unlocked everything that there is to unlock.
"We do still need to make improvements for sure but at least we have some time after testing to again learn more for Australia.
"[Ferrari] still seem strong. Obviously, as always from testing to Melbourne, a lot of things can change, but they do have a strong package.
"I still think we do need to unlock more from the new package to be able to really compete with them properly."
Bottas endured a difficult season in 2018, failing to win a single race as team-mate Lewis Hamilton won his fifth drivers' championship.