Haas F1 boss Gunther Steiner says his team is "back to square one" for the Australian Grand Prix despite its promising form during pre-season testing.
Despite not using the softest tyres during the winter running, Haas driver Kevin Magnussen finished sixth-quickest overall, around a second slower than Ferrari's Sebastian Vettel, who used hypersofts for his best time.
Haas' pace led to Lewis Hamilton saying the team will be "up there this year", the reigning champion labelling its cars as "very, very fast".
While Steiner welcomed the praise, he insisted the team has not achieved anything yet and remains cautioned about its prospects.
"It's flattering, but we are realistic. We are cautiously optimistic about it," said Steiner in Australia on Thursday. "We don't put ourselves under pressure because of the test results.
"We are all cautiously optimistic but we know we have a lot of work to do to get the result which apparently seems to there. It's not done yet. There's nothing done yet. We haven't achieved anything.
"We are good in testing, but we didn't get any points, we didn't get any trophies so we are back to square one."
He added: "We are cautiously optimistic, but again, testing is not qualifying or a race, so there's still a long to way and again we will know more on Saturday about where we really stand compared to the other ones.
"We know where we are, but even if you are magic, if somebody's mega magic, you are still behind them."
While his team boss downplayed expectations, Romain Grosjean reckoned there is reason to be optimistic, the Frenchman expecting Haas to be within half a second of Ferrari.
"I think Ferrari, everyone talks about the engine, it's a big part, but we have the suspension, hydraulics, the gearbox as well, and all of that is a big part of our car," said Grosjean.
"That's why when Gene [Haas] says 'I want to be within half a second of Ferrari' and I don't think that's unrealistic."
"We're going to fight some big really teams, which is amazing in our third year. Let's see what it's like but we just focus on our own job and not trying to make plans for reaching Mars or Jupiter or Neptune or whatever."
Steiner, meanwhile, is positive Haas has a solid development plan for the season.
"We have a good plan in place, but I don't know what the other ones are planning to put in, so it's difficult for me.
"We can go with history but again, even spending a lot of money doesn't mean all the time that you get the results. Even if you spend 10m or 20m in updates it doesn't mean that you get for every million five points in aero efficiency.
"We have a good plan in place compared to ourselves from last year, to bring more and better updates, because we have matured as a team. But if we can keep up with them or not I don't know sitting here."
Additional reporting by Edd Straw and Adam Cooper