Norris finally broke his duck in F1 on his 110th start, taking a convincing win at the Miami International Autodrome albeit with help from a well-timed safety car.
It was Norris' first win in a motor race in over 2200 days, having previously claimed 15 podiums in F1 before climbing the top step.
Norris admitted that finally taking his first victory was a weight off his shoulders, but according to team principal Stella that could also be said of the team itself, because it was finally able to give the 24-year-old a car that was quick enough to do so.
"I think [not winning] was a bit of a weight on his shoulders, but it was a weight on our shoulders as well ," Stella said when quizzed by Autosport.
"We knew as soon as we made winning material available to Lando, he would have delivered. So we felt the responsibility and I have said that many times, that it is up to us, it is not up to Lando.
"But credit to Lando, he kept developing over the winter, especially looking at improving in qualifying and delivering laps that sometimes don't have to be 100% when you have a fast car, just be there. I think he is doing that."
The Italian added: "That's for me a testament to how ready he was, and also if we look at what he delivered in podiums with a car that sometimes wasn't really a podium finisher on merit, for me Lando is in a very strong journey."
Stella praised Norris for keeping his powder dry in the first stint on medium tyres when stuck in traffic, only to then deliver one fastest lap after the other once he found clear air, pace that even had Red Bull's Max Verstappen rightly worried.
"I have to say that his race management is very mature," said Stella. "As soon as he saw there wasn't much to do after the first lap, he started to save his tyres because he knew his race would come at some stage.
"The pace he was able to pull off when the cars ahead of him pitted, that was quite incredible. He was getting the most out of the material he has.
"We needed to provide him with winning material. And as soon as we did it, he achieved it."
