McLaren plans to be more aggressive to close Mercedes' F1 margin

The team took an early lead in the 2014 F1 constructors' championship after Kevin Magnussen and Jenson Button were classified second and third in the season-opening Australian Grand Prix.

Boullier says that Mercedes still enjoys a near one-second advantage over the field however, meaning that his team must now focus its efforts on significantly improving its outright speed, with a view to closing the performance gap by the Spanish Grand Prix.

"It's true that Mercedes has some pace [advantage], maybe between half and three quarters of a second over the rest of the field," Boullier said.

"But as for McLaren, we focused a lot of our winter on building a solid and reliable car, because we believed - and Australia confirmed our strategy - that reliability was key to taking big points at the beginning of the season.

"Now we are pushing very aggressively on performance development.

"Clearly we need to catch up with Mercedes."

Boullier said McLaren was not fixating only on Mercedes however, warning that other teams would also be threats once they get on top of early 2014 teething issues.

"Some other teams have not performed well so far, but clearly once they are delivering full power they will be very fast," he said.

"Our target is to catch up by Barcelona, and then build up over the first few races in Europe."

McLaren already has a significant upgrade package planned for next weekend's Malaysian Grand Prix.