Senna finished ninth at Monza, in only his second outing for Renault, and scored the first points for his family since his uncle Ayrton triumphed at the 1993 Australian Grand Prix.
Boullier believes that the result will be a boost to Senna's confidence, which should allow him to lift his game over the remainder of the campaign.
"He is doing well and steadily progressing, so it is the best way I could have dreamed, to be honest," said Boullier about Senna's performance. "He didn't race since last year, and he doesn't have great experience: starting in Spa with rainy conditions and here is not the easiest track to race in F1.
"On the first lap he was 18th, so his consistency was good enough, not
perfect, but good enough. And clearly he pushed at the right time. Thestrategy was not bad and we had some help with some retirements. But
it is good for him, for his confidence; for the team and it also shows
that the latest upgrades we had on the car are definitely working."
When asked by AUTOSPORT what he expected from Senna over the rest of the season, Boullier said: "I expect him to keep progressing like this. I believe the more he will deliver like he is doing, the more confidence he will get and the more he will be able to deliver.
"He still has a lot of potential because you could feel during the weekend that what he is doing or what he is saying, is definitely fitting well. He wants to do well. I expect him to challenge Vitaly."
Senna's improved performance could help him secure a seat at Renault in 2012 if Robert Kubica does not return from injury, but Boullier has made it clear that thoughts on the future are far from his mind at the moment.
"It is too early," he added. "One problem at a time."