Sergio Perez says that Force India has been 'pretty special' across the opening four races of the campaign, considering the squad's slow start to 2015.
Force India only introduced its 2015 car at the final pre-season test, with the outfit effectively waiting for its B-spec car to arrive in time for next month's Austrian Grand Prix.
Despite being behind their competitors in terms of development, Force India has racked up 11 points across the first part of the campaign to sit in eighth place in the standings, close to their midfield rivals.
"I think the first four races have been better than expected," said Perez. "To be 10 or 12 points behind Red Bull, is a massive effort for us coming out of the first four races, so I think we need to be optimistic.
"Obviously, we've been lacking pace, so I think the effort that has been done in the first four races has been pretty special considering what the basic pace of the car is."
Perez nonetheless expects Force India to have another challenging race in Spain this weekend.
"We're going to have another race similar to the first four," he said. "I think this one is going to be a particularly difficult one for us considering Barcelona, how hot is the track and the level of downforce is what we're lacking the most.
"I expect to have a difficult one, but on the other hand, not any more difficult than other weekends. [I'm] optimistic, but [it's] difficult when you don't have any upgrades. I think some of the teams are bringing some upgrades, so let's see what we can do."