Haas team principal Guenther Steiner has labelled Williams as the only outfit his team can compete with this year.
Before the start of this season, Haas confirmed it would not be developing the VF-21 and was instead focused on the opportunities presented by the regulation changes for next year.
Across much of the opening Bahrain Grand Prix weekend, the team was rooted to the foot of the timesheets and only avoided a back-row lock-out for the start after Aston Martin driver Sebastian Vettel was handed a penalty.
In qualifying, Nicholas Latifi in the slower Williams was half-a-second faster than Mick Schumacher's best effort, while in the race the young German was last of the 16 who finished and team-mate Nikita Mazepin crashed out on lap one.
Steiner has conceded Williams is the only team potentially within the reach of Haas. He said: “I would say if we can take the fight to Williams, that is about it for what we can do.
"I am very realistic about that and we are not putting any effort into doing anything more than that.
“We will try to get the biggest amount we can out of the car, to get our drivers better prepared.
"That is where the most time is at the moment, just getting them the most experience and that is what we want to do so they are ready when we have a better car. That is just how our plan is for this year.”
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