Mercedes motorsport boss Toto Wolff believes his team will face a "difficult" fight to complete a job that is only half done in his eyes and secure the Drivers' Championship for Lewis Hamilton at the Mexican Grand Prix.

The Briton needs a top-five finish to claim a fourth Formula 1 title and complete a quadruple-double for the German manufacturer after they clinched the Constructors' crown last weekend in Austin.

Yet reflecting on what was a "special" result and a "very proud achievement" for Mercedes, Wolff was more impressed by how Hamilton went about clinching his seventh win of 2017.

"Just as important was the way we won the race, claiming pole position and then controlling it from the front, after passing our direct rivals on track," said the Austrian.

“That kind of performance confirmed we are continuing to develop the car in a good way - and applying the learning from our difficult days, to iron out the inconsistencies we saw earlier in the season.

“Lewis is doing a superlative job, and we saw he was in control of the race at every single point," he added. "Valtteri got swallowed up by the cars that converted to two stops, but he showed very strong pace during the Grand Prix and took another step forward in how he was using the car. There is still more to come from him.”

Looking ahead to this weekend in Mexico City, though the title race appears to be a foregone conclusion, Wolff insists Mercedes will continue the same approach they have had as they leave nothing to chance.

“When we set our targets at the start of the year, it was to become the only team to win both championships across a major regulation change," he stated. “We now have to complete that job with Lewis, who is in the best possible position with three races remaining.

“We know that anything can happen in this sport and that the tables can be turned on you very quickly. So there will be no let off in our vigilance and attention to detail in these final rounds. We will be racing to win.”

Hamilton too, claims he will not be taking it easy as he looks to repeat his victory from 12 months ago.

"At the moment, I’m just focused on winning, clearly, and I’m enjoying driving more than ever," he said. "The challenge, the pressure’s intense. Just always want to elevate yourself and shine brighter each time you get in the car.

"There’s still three races to go. In my mind, I’ve still got a lot of points available. So I don’t think until it’s ever properly done and sealed you can ever get ahead of yourself."

Though the layout of the Autodromo Hermanos Rodriguez would seem to suit Mercedes, with a very long main straight and a fast, sweeping infield, one of the unique factors that teams have to consider could actually expose an ongoing weakness of the W08.

"It will not be easy to achieve this weekend in Mexico, this is an unusual circuit where the cars run at maximum downforce owing to the high altitude,” Wolff explained.

“Some of our most difficult weekends this season have come with the car running at maximum downforce, so we expect a tough and close-fought battle with both Ferrari and Red Bull. It will be important to be at the very top of our game if we want to get the job done.”