Mercedes chief strategist James Vowles has conceded catching Ferrari in the F1 constructors' standings is a "tremendous ask" despite the gap shrinking at each of the last two weekends.
Lewis Hamilton and George Russell have steadily pulled back the margin to early pacesetters Ferrari, with the Silver Arrows outscoring its rival by 27 points across races in the United States and Mexico.
But with only Brazil and Abu Dhabi remaining before the chequered flag falls on the season, Mercedes is running out of time to hit its target of overhauling the Scuderia.
“It's very clear what our internal goal is," said Vowles. "We are here to finish second in the championship, and every single race that we can start pulling that points gap down is a success.
"In Mexico, we took just 13 points out of them so there are still 40 left to go with two races. Fortunately, one of those is a sprint race.
"I think we have a package now unlike the beginning of the season or the mid-season that can really bring the fight to them.
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“But 40 points is a tremendous ask. It will need us really having everything perfect, everything right and Ferrari perhaps to give us opportunities to open the door for us to pick up second.
"What I can tell you is that we are not giving up until the chequered flag in Abu Dhabi.”
Mercedes upgrade yields results
Mercedes unveiled a controversial new front wing in the United States with fasteners that appeared to provide a secondary aerodynamic benefit.
Although this adhered to the wording of the regulations, the FIA voiced concerns over the development which led the team to make changes before running it in Mexico.
Asked if the new part had shown the expected improvements in performance, Vowles added: "Yes, is the answer to that one.
"We fitted it on Friday, in a modified form. You would have seen some level of discussions of what we had initially.
"It was in a slightly modified form but otherwise it was fitted to the car and performed as far as we can tell through our metrics.
"We measure pressure tappings on the car and loads at various locations, and it was performing and remained on the car the remainder of the weekend.”