Eric Boullier believes the success of the Renault team's F-duct was responsible for the performance gain that allowed Robert Kubica to finish on the podium at Spa on Sunday.
Kubica rain second to Lewis Hamilton after Sebastian Vettel had taken out Jenson Button, but slipped to third in the end after Mark Webber got by when he overshot the Renault box during his pit stop. But Renault team boss Boullier was still delighted with the result and the pace of the car, which was able to stay with the front runners throughout.
"I am pretty sure than half the performance gain we made today was down to the F-duct," he told AUTOSPORT. "I have to pay tribute to the team because everybody was impressed that we fitted the cars with the F-duct and it worked straightaway – and was matching the simulation figures. It is clearly a good step forward.
"The blown floor was clearly very challenging to make it work properly and it takes a couple of races to do it, and that is why it looks like we didn't improve much. The F-duct clearly was a bit step forward and now we have the same tools as everyone else on the grid it is pleasant to see our car is matching the pace of everyone else on the grid."
Boullier reckons Renault can now overhaul Mercedes for fourth place in the constructors' championship.
"I would be very pleased to have more podiums of course," he added. "It is definitely realistic when I see our performance level, and clearly now we set our expectations a little higher and we definitely need to take this fourth place."