The American outfit will travel to Australia next week for the season opener - hoping to improve on last season's shambles with pit-stops forcing Grosjean and his team-mate Kevin Magnussen to retire from the grand prix.
Haas produced some encouraging lap-times in pre-season testing in Barcelona and Grosjean is hoping to continue some of the progress when he hits the Albert Park Street Circuit in just over a week's time.
"The most important thing was to get a good feeling in the car early on," Grosjean said on the Haas VF-19. "When you get that good feeling, you know the car is well-born.
"That's important to start the season - to be able to start on a high. It went well. Reliability, we had a few issues, but we've been working well to sort them out. I believe we're now ready to attack the first race in Australia.
"Obviously, there's always more and more you want to do, but then it's becoming circuit-specific. Now it's about getting the baseline setup in Melbourne and then fine-tuning for Bahrain, China and so on."