Perez believes Spanish GP progress crucial for Force India F1 team

Force India has enjoyed its best ever start to a season - having scored a podium finish in Bahrain and currently holding third place in the constructors' championship.

But with the fight behind pacesetter Mercedes being so close, Perez is under no illusions that a slip-up in its development push could prove costly to its ambitions.

"It is crucial that we do a good step for Barcelona," Perez told AUTOSPORT. "It will be crucial to keep us in the [right] rhythm.

"We are in a good rhythm as a team and we need to keep progressing from there."

Force India has benefited from the impressive work of engine partner Mercedes, and knows that the key battleground from now will be in improving the aerodynamic qualities of the car.

"We need more downforce overall," added Perez. "You see everyone looking for rear downforce, and it would be good for have some downforce in general.

"I hope [the update package] is big enough to get us fighting with the big boys. It will be really good if we can keep this car going, and there is good room to improve."

Team-mate Nico Hulkenberg has high hopes that Force India can match the development rate of the bigger money teams it is fighting with.

"I think we can keep up," he said. "It is obviously hard to say for sure, but what I hear is that there is some good work done and stuff in the pipeline.

"I am optimistic we can have a competitive season."