De Vries was called in to replace Alex Albon at Williams for the remainder of the Monza weekend on Saturday when the latter was ruled out with appendicitis.
The one-time Formula E champion qualified 13th – though started eighth due to grid penalties for others – and went on to finish his debut F1 race in ninth despite receiving a reprimand for erratic driving under the late safety car.
With Nicholas Latifi's future at Williams uncertain and several other seats available in F1 for 2023, de Vries' strong maiden outing has come at the right time.
Asked if he felt the Italian GP was something of an audition for him in regards to earning a full-time seat in 2023, the Mercedes reserve said: "I mean, any time you're in the car you're expected to do a good job.
"And any time you get a chance to drive a Formula 1 car it is a kind of job interview and an audition.
"You've got to take those opportunities, but you've also got to use them sensibly because there's always a trade-off of doing too much and too little.
"But I am just grateful that it worked out well and played into our hands. We took some points and it was a great performance. And no one can take that away from us."
On Saturday at Monza, Lewis Hamilton said De Vries deserved a place in F1.
Asked by Motorsport.com if he agreed with the seven-time world champion's comments, he added: "You know, I feel like I wouldn't be standing on this grid [if I didn't deserve it] and I think this weekend has been a good performance.
"But we're always expected to do a good job and it's not up to me to decide any driver line-up.
"This world is very volatile and it's not only merit counts. So, it's out of my control.
"But this no one can take away from me, so regardless of the future whether I'm here or not, I can look back on a proud debut and first moment in Formula 1. I enjoyed it."
