Lando Norris lost an estimated 0.2 seconds per lap in Florida following a Turn 1 hit from Nyck de Vries that damaged his floor. He finished 17th as Oscar Piastri classified in 19th.
The team had considered retiring Piastri altogether as the rookie worked to manage spiking brake temperatures while a fix for a brake-by-wire hydraulic system fault was sought.
With that misfortune arriving straight after a 9-11 result in Azerbaijan when a revised floor was introduced, the dismal Miami showing has brought McLaren back down to earth.
Team principal Stella said: “The main takeaway is that after a decent weekend in Baku from a performance point of view, we had a reality check.
“The information we gained here helps us understand that some development directions still need to be pursued, like improving the car in off-brakes, off-throttle.
“At the moment, the car just doesn't work in this condition. At tracks like this, this becomes too much of a limitation.”
The Italian added that McLaren’s only shot at major progress in the race would have come from an incident to induce a safety car and shake up strategy. But the full 57 laps ran without a retirement or a single yellow flag incident.
Stella continued: “We would have needed today some events in the race, a safety car or so, but nothing happened.
“So, the limitations for a performance point of view could not be overcome thanks to some situational elements. We go away with no points.”
Norris was particularly dejected in the post-race media pen, saying that McLaren suffered particularly because AlphaTauri - with Yuki Tsunoda finishing 11th and de Vries 18th - was the only other team that underperformed.
He said: “The track doesn't suit us, longer corners don't suit us, the temperature doesn't suit us, track surface doesn't suit us. There are many different aspects of it all.
“No one was slow either this weekend. Maybe the AlphaTauris were the only other slow car. Everyone else was pretty quick.
“The Alfa Romeos were mega fast, Haas were mega fast. The Alpines were way quicker.
“I wouldn't say we were that much different to where we have been, it's just everything else was a big step forward and a lot of this is just down to car characteristic, in my opinion.”
On the first-lap knock with de Vries, Norris said: “I don't know what happened. I just got hit.
“He's done that a bit lately, so he needs to try braking a little bit earlier, but it didn't change my day.”
