The Woking-based racing outfit finished third in last year’s Constructors’ Championship, but they only had the fourth or fifth most-competitive car at most tracks.
This year, in the hands of Lando Norris, McLaren’s 2021 challenger has been exceptionally close to Mercedes and Red Bull at some circuits, such as Imola and the Red Bull Ring.
Stella has said they were “surprised” to be so close to the front-runners on some occasions.
“We were a bit surprised at some races to be able to compete so closely with Mercedes and Red Bull,” Stella said.
“For example, the second race in Austria, we were genuinely very close to pole position and genuinely quick in the race.
“Even if in the race normally, Red Bull and Mercedes tend to open up the gap compared to the midfield, that is a trend that we have seen throughout the year.
“I think the reason is certainly from last year, we are happy with what we have been able to improve through the power unit. It has been important but we are not the only car running a HPP [Mercedes High Performance Powertrain] power unit.
“Aston Martin is running a HPP power unit as well so I think this is credit to the development of the chassis that McLaren has been able to achieve, in a way, some operational aspects and I would like to mention also the drivers,” he added.
McLaren are locked in a battle with Ferrari for third in the 2021 Constructors’ Championship, and they are currently both level on 163 points apiece.