Aston Martin and Haas have both taken the decision to start their two cars from the pitlane for the United States Grand Prix.

In Aston Martin’s case, the team suffered its worst qualifying performance of the season on Friday evening at the Circuit of the Americas, compounded by a lack of track time during the sole practice session as it attempted to evaluate a new upgrade package.

Stroll completed only five laps due to a brake system failure, which in turn compromised Alonso as the team checked over his car’s brakes systems to ensue there would be no repeat, resulting in the two-time F1 champion managing only 19 laps.

In qualifying, Alonso and Stroll were both knocked out of Q1 for the first time this season, and would have started 17th and 19th respectively.

But the team has opted for pitlane starts as it allows them to make setup changes which will assist with data gathering as it looks to build on its updates.

Deputy technical director Eric Blandin said: “So in FP1, because of a mistake on the simulation, we put too much blanking on the front brakes, so they effectively caught fire.

“So that’s the reason why we couldn’t run more than two (quick) laps with Lance in the morning, and that really put us on the backfoot for the whole weekend, and the car is far from its optimum setup with the new package.”

Stroll’s weekend suffered further when the team was forced to retire his car during Saturday’s sprint due to a water pressure issue.

Given the team’s lack of understanding with its car so far, despite Blandin confirming the update package is “performing as we expected”, he added that in order to optimise the setup it feels it is necessary “to start both cars from the pitlane”.

“We are effectively changing the setup because we think there is a lot more performance to come from the car,” he declared.

“But we have taken the pragmatic approach to start one car with the Qatar spec, and the other with the new package.”

Alonso will revert to the older spec of car, whilst Stroll will be handed the opportunity to further evaluate the new spec. The setups on both cars will be “something similar”.

In terms of where the setup will be targeted, Blandin said: “Generally, our performance in high speed was pretty decent relative to our competitors. We just suffered more in the low speed.”

It is the same for Haas in terms of changing its setup and then being able to further evaluate its cars as the team has introduced its biggest in-season upgrade package in its eight-year history.

Magnussen and Hulkenberg were due to start from 14th and 16th respectively. Both will now sport a different rear-wing assembly.