Toro Rosso technical director Giorgio Ascanelli said the team's qualifying performance at Spa was evidence of a genuine stride forward, as Jaime Alguersuari claimed the best starting position of his Formula 1 career in sixth and Sebastien Buemi narrowly missed out on joining him in the top 10.
Ascanelli acknowledged that issues for the Force Indias and Michael Schumacher might have eased Toro Rosso's path towards the top half of the grid, but was still delighted with his team's performance.
"Our good result with both cars is down to the work we have done so far this weekend, although we have to accept that both Force Indias and Schumacher might have been expected to be ahead of us," said Ascanelli.
"However, it is also true to say our drivers did not make any major mistakes so the result is well deserved. I am sorry for Sebastien whose only error up until now came on the lap that mattered in Q2: otherwise he could have been tenth and been able to fight in Q3.
"The clearest indication that our car has improved, through various updates we have introduced here, is the fact we have been slightly better than Sauber in both the dry and the wet. For the first time this season, we have seen progress with our DRS and that is down to the work of the aero team on developing this aspect of the car."
Alguersuari was similarly thrilled with his result.
"This was my best ever performance and the best for the team this year," he said. "I think I have to be very happy with this and also because my team-mate came very close to Q3, which shows we have done a good job, not just on the car but in the way we managed the session, being the first out of the pits to get a clear track.
"The weather helped, because the car worked very well on the intermediates and the extreme wets, but we have also been quick in dry conditions. We knew we had a better car here than in Hungary and we have learned a lot about it so far this weekend. Certainly the DRS is now working better than ever before."
Buemi had been in the top 10 for much of Q2, before a slight mistake on his crucial final lap.
"It was not easy this afternoon, because the track dried very quickly after the rain actually stopped falling," he said. "Therefore you had to get a good lap at just the right time. I managed to do that right up until the end, when I made a small mistake.
"I am a bit angry with myself for that, but 11th is still a good place to start the race tomorrow."