Having earned a 20-second post-race penalty in Belgium for forcing Ferrari’s Fernando Alonso off-track, Magnussen was hit with a five-second stop-go penalty at Monza after the stewards deemed he had forced the Williams of Valtteri Bottas off the road at the first chicane.
However, whilst accepting that the penalty handed out in Spa-Francorchamps was “deserved”, Boullier said that the punishment in Monza was more debatable.
“I think he was unfortunate to be penalised,” the Frenchman told a McLaren-Mercedes phone-in on Tuesday. “We believe (the incident with Bottas) was a normal move and legitimate defence.
“I don’t think he will have to change his approach - Spa was a one-off and Monza, for us, was unfortunate. I think he needs to keep building up his confidence by doing what he’s doing.”
Asked how impressed he was by Magnussen’s uncompromising racecraft against some much bigger Formula One names, Boullier said: “It’s clear that he’s stepping up. He might be punching above his weight because he doesn’t have the car to be fast enough for a better result. But he’s trying his best.
“I think it’s good for him, good for the fans and good for the show to see this young kid, this young Viking, fighting with the big boys. Obviously his self-confidence is growing massively and that’s good for his racecraft which is only going to get better and better.”
Magnussen, who lost a total of nine positions and 14 points as a result of the penalties handed out in Belgium and Italy, is currently 12th in the drivers’ championship with 38 points. His best result to date remains the second place he scored on his Grand Prix debut in Australia in March.