Pedro de la Rosa hailed HRT's step forward after qualifying for the Malaysian Grand Prix at Sepang on Saturday.
The Spanish squad, which had failed to get its cars on the grid for the season-opening race in Australia, will start the Sepang event from 22nd and 23rd positions.
De la Rosa, who outqualified team-mate Narain Karthikeyan, praised the team's progress since Australia.
The Spaniard, however, is under no illusions for the race, which he reckons will be very hard for HRT.
"It was a good day," said de la Rosa. "From the first lap in the morning I felt that the car had improved notably and we improved our times significantly. We've lowered our time by more than a second from yesterday to today and every time we modify something new we're going quicker.
"We could have improved our times even more during the qualifying session. I was only able to do one lap but it was enough. The important thing was to qualify and we did. The team has proved that in a short amount of days it managed to have the DRS ready and improve the power steering and other aspects of the car.
"We've taken a huge stride and I'm very satisfied because of that. Now we have to see how tomorrow goes in long distance because it will be the first time we string so many laps together, which won't be easy in this weather."
Karthikeyan was also pleased with his day despite some overheating problems - the Indian hoping for rain in tomorrow's race in order to ease the team's worries over this issue.
"The conditions changed a lot from the morning and the track was much more slippery but we qualified for the race, which was our first objective for this weekend and a positive step from Australia," he said.
"We had to change our strategy a little bit today because of some heating issues, and it worked, but now we must focus on overcoming those issues and aim to finish the race. It would be good for us if it rained because that keeps the car a bit cooler but, no matter what, we'll have to give it our best and try to put in a good performance."