Paddy Lowe ambitions to upgrade Williams' performance level this year with the team's new FW41, but expects fierce competition from mid-field rivals.
Williams launched its 2018 charger in London on Thursday evening, images of which showed an aggressive and bold design, the first overseen by Lowe since joining the team in early 2017.
On a relative basis, Lowe is expecting massive competition from the likes of Force India, McLaren and Renault but the 55-year-old engineer's main target is to reduce Williams' deficit with the top-three front-running teams.
"We are trying to achieve an element of step change and not just a progression," explained Lowe.
"We were two seconds or so a lap slower than the front runners [in 2017] and that is something we would like to close up considerably. So we are looking for a step change."
"We are hoping to be well up there, but we recognise some incredible competition out there," he added.
"Obviously the front three teams are established in a good position. We have Force India who did a terrific job last year and beat us in the championship.
"We also have McLaren with a different engine: they will be a threat. And we have Renault emerging. So that is already six out of the nine teams we are competing against. We don't take anything for granted."
Lowe also said the team was still in the process of optimizing the FW41's design despite reaching most of its virtual performance targets.
"Broadly we've hit our targets, but we are always pushing until the end," he said.
"We have got to the stage where we are finding things in the tunnel and it's on the cusp of 'can we get to them for the first race?'
"We've hit performance targets we set internally, but there are a couple of caveats. Are those targets ambitious enough and will those transfer to the track? That remains to be seen.
"One of the things we can measure is on absolute performance. So while we are reluctant to say we want to come third, or fourth or fifth because we cannot predict what others have done, we would like to see a lap time gain against the guys who were taking pole position last year."
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