Bob Bell is cautiously optimistic ahead of the new season as he says Mercedes have a "better understanding" of their W04.
Mercedes showed an impressive turn of pace during the final pre-season test as Lewis Hamilton and Nico Rosberg set the pace on the final two days.
The duo ended the test first and third overall with Rosberg having set the fastest time at the Spanish circuit. The W04's performance has given the team reasons to be optimistic.
"Last year we looked reasonably competitive at the end of the winter testing but I think we knew from what we knew about the car, and the way it was behaving, that it wasn't rock-solid, that we could get caught out," Bell told Autosport.
"This year we're a little bit more confident that at least that the car's behaving more like we'd expect it to.
"[We have a] better understanding of what it's doing well, what it isn't doing well, and that gives us a little bit more cause for optimism regarding a more consistent season."
The technical director, though, was quick to curb expectations especially in light of Mercedes' erratic season in 2012.
"I think we're naturally cautious; we're not taking anything for granted.
"We know what we did wrong last year in terms of managing our programme the development car and there were other infrastructural reasons that we were struggling a little bit with in the second half of the year.
"Sustained pace of development is crucial these days in F1 and of course we have to prove that on tracks.
"We've learnt from [last year], we're pleased with the progress we've made, but we really need to demonstrate that we can maintain that over the course of the season.
"We've made a lot of changes to the organisation, the way we do our jobs in the last 12 months and I'm reasonably optimistic that that's settling down and that we can deliver."