Massa completed 64 laps in Jerez and was sixth fastest.
"The first impression is definitely a positive one," he said. "We did not run as much as I had expected, but that’s normal when you are testing a new car. On a track like this where traction counts for a lot and the tyres feel it, I got a positive feeling as far as the balance of the car is concerned and I think that, especially at the rear, we are going in the right direction and it feels more solid."
"It’s definitely a different situation to last year, because the basis for this year is in much better shape. There is still a way to go before we understand the true behaviour of the car, but we are on the right road. There is still a great deal to do, as far as testing and development are concerned, but I am confident that this year, we will not lose time in understanding, as happened in 2012, what was the problem and how to solve it. Now we have a little more than a month to concentrate on the job, to be as well prepared as possible for the first race."
Massa will continue to drive the F138 on Wednesday.