McLaren’s technical boss has shed light on where the MCL35M struggled throughout the 2021 Formula 1 season.

McLaren finished the year fourth in the constructors’ championship with a race win to its name courtesy of Daniel Ricciardo in Italy.

But while McLaren enjoyed strong pace in Monza, taking a one-two with Lando Norris trailing his team-mate to the flag, James Key has admitted the car was weak in longer, slow-speed corners.

“I think what we’ve seen with straight line braking, which is one of our strengths, and high-speed corners kind of reflects the sorts of performance we can generate with the nature of the car we have,” said Key, McLaren’s executive technical director.

“What we’re missing is we’re trying to work on this between ‘20 and ‘21 is to generate that performance in low-speed.

“We know why we’re not quite there yet,” he added.

“I wouldn’t normally say this in a season, other than perhaps the last race with change of regs coming, but that’s some of the issue.

“The car isn’t quite as robust as it is in high-speed, in the low-speed corners.”

The 2021-spec MCL35M was an evolution of the previous year’s MCL35, with the notable addition of a Mercedes power unit.

As such, the broad performance of the car, and its fundamental characteristics, were largely unchanged.

In addition to the 2020 cars carrying on another year, changes were made to the floor in an effort to reduce downforce.

While working to recover that loss of grip, McLaren did so with a view to addressing some of the car’s inherent weaknesses.

“What we found last year [2020] is we had similar traits. In fact, we had it in ‘19, as well,” Key explained.

“We also had a very, very severe wind sensitivity last year [2020] as well. They all point to kind of similar circumstances, and some of the make up the car aerodynamically.

“So a lot of the work that went into the ’21 car – recovering the downforce with a few tweaks that are made on the floor, et cetera – were to specifically try and address some of these problems.

“Unfortunately, the nature of them isn’t something that’s a bit of a silver bullet, where you just switch it on and suddenly it’s great – it takes time to make them work. You can make them work fastest, but you lose the strengths in other areas.

“That was the battle we were up against, that is why we knew Zandvoort would be difficult; long, low-speed corners where the grip level at low-speed is really critical.

“Equally, how we kind of knew that Monza would be strong, because it’s almost everything is really kind of high-speed apart from a couple of corners there now, certainly Parabolica, but low-speed are a quick change of direction, short-duration corners. So it all stacks up for us.”

Key added that the traits of the MCL35M had evolved over recent years, and could be traced back to before his time at the squad.

As a result, a degree of focus was placed on expanding the car’s operating window in an effort to counter its weaknesses.

“I think had we had the same regulations again, we would exclusively have looked at low-speed,” he admitted.

“I think for next year [2022], it’s such a different car and your choice is actually quite different.

“You’re trying to achieve a very similar goal with the way the car behaves, because it’s still the same rules apply as to what makes a car quick, but the way these cars behave, aero wise, mechanically, we’ve got to consider as well as really substantially different.

“So, it’s less of a choice where you face different choices or different challenges with the ‘22 car,” he continued.

“But yes, we wouldn’t want to be recreating what we did in ’21, I think we want to have a more balanced situation across a wider range of tracks.”

McLaren will unveil its 2022 car on February 11.