Toto Wolff admits that his team is at a loss to understand why its performance varies from weekend to weekend.

Ahead of the summer break the German team scored three victories almost in succession, with George Russell winning in Austria and teammate Lewis Hamilton standing atop the podium at Silverstone and Spa, the latter win after Russell was disqualified.

However, since the season resumed, the Silver Arrows performance has been somewhat erratic, allowing McLaren and Ferrari to gain the upper hand. Indeed, in the four races since, the team has scored just one podium finish.

"This variance in performance from race to race, or over a few races, is very difficult to compute," Wolff tells Autosport, "because what looks like an unchanged car can go from race winning to P6."

Pointing to the examples of Red Bull and Ferrari, Wolff claims that in reality McLaren is the only team which "is not a victim" of fluctuating performances.

"They have such a solid baseline and a less narrow window than all of us, that they're able to keep the performance stable," he explains.

"All of the others bounce between exuberance and depression," he continues. "Before the summer, everyone wrote off Ferrari. But they have come back very strong.

"Before the summer, it was Mercedes who was the leading team, and clearly not today anymore. So it is so intricate to identify those performance contributors that at times even that most clever people are lost."

Like Red Bull and Ferrari, Mercedes has suffered as a result of recent upgrades that took the team in a wrong direction.

"What everyone seems to find out is that more downforce doesn't always translate into better lap time," says the Austrian. "Now, this is not the sensational news of the century, but it is the interaction between track, temperatures, tyres, balance, aerodynamics, and driver impulse, so many variables, that if you get all your ducks in one line, you are fast. But if there is just one factor that is out of line, you can look quickly very bad."

However, those three wins are clear proof that Mercedes can get it right and therefore serve as the perfect benchmark.

"Every session now is, in a way, interesting, because we are able to benchmark against the good races," admits the Austrian. "We can see what's different on the car, what's different on the track, what happened with the tyres and all of that.

"It's not like we don't know that this car has pace. It's a race winner."