McLaren went into the inaugural race weekend around the streets of Vegas with muted expectations but, while similar pessimism proved unwarranted in Austin, Mexico or Brazil, it did turn out to be justified on the low-downforce street circuit.
Lando Norris was knocked out by former team-mate Daniel Ricciardo by a mere 0.020 seconds in Q1 to qualify 16th, while Oscar Piastri followed in 19th in what has been McLaren's worst qualifying performance since it upgraded its MCL60 in the summer.
But, while McLaren's specific weaknesses in low-downforce and low-speed corners played their part in its double Q1 exit, Stella explained that the team's main stumbling block was the execution of the session itself.
"The fact that we were not performing very well left us on the back foot because we were very focused on trying to squeeze some performance out of the car," Stella explained.
"There were quite a lot of changes from yesterday, which finally actually added some performance.
"But we haven't done enough work because we're being on the back foot in understanding how you should actually use the tyres for qualifying."
Both Norris and Piastri opted to only use one set of soft tyres compared to two sets for their competitors, based on evidence from final free practice that Pirelli's soft compound could last for three qualifying laps before degrading.
Source: Autosport