Fernando Alonso says the progress made by Ferrari is a "very good sign" despite qualifying ninth in Belgium.
The Spaniard lost out by mis-timing his best lap in mixed weather, but the Ferrari had been more competitive than in the last three races.
Alonso has identified the next three races as vital for his title hopes.
"It is a very positive sign in the first of these important three races we saw Ferrari fighting for the top in first and second qualifying," he said.
"After what we saw in the conditions if we can pass people in front it seems we have the pace to challenge [for] some good positions [in the race]."
Alonso was fastest in wet conditions in the first part of qualifying and second in the dry in Q2.
But when it came to decide the top 10 grid positions he crossed the finish line too late in a wet-dry session to get in a lap when the conditions were at their driest at the very end.
Alonso believes this race at Spa-Francorchamps, the next at the high-speed Monza track, and the subsequent event on the tight Singapore street track will define the drivers who are title contenders because of the differing demands of the tracks.
He is third in the championship, 39 points behind leader Sebastian Vettel of Red Bull, a point adrift of Lotus's Kimi Raikkonen and nine ahead of Mercedes driver Lewis Hamilton.
"We felt a little bit more competitive today than in the last qualifying sessions in July," Alonso said.
"We need to check in the next races - here is medium downforce, Monza will be also a unique circuit in terms of set-up. So here, Monza and Singapore will tell us how much progress we need."
He said that the progress with the car had come from Ferrari deciding to focus more on a stable, consistent aerodynamic performance rather than chasing the maximum potential downforce and creating instability in the car.
"All the new components that are arriving in the car are maybe not so obvious but there are some steps we have to do in terms of developing the car for more consistency," he said.
"In Silverstone [where he qualified an uncompetitive 10th] we understood that the peak of the performance in terms of the aerodynamics is nice to have but it is also nice to have a good and consistent downforce level throughout the corners, not only in one part of the corner.
"So we are working on that and the car seems little more consistent, more stable, easier to drive and you can complete the laps better.
"So there is not a revolution in aesthetics [the way the car looks] but the car is progressing well."