Sergio Perez believes Force India will have a good opportunity at the next two races to regain the ground they lost before the summer break.
The Mexican and his team-mate Nico Hulkenberg regularly battled for top five places during the opening few races of the 2014 campaign, but they slipped off the pace at Silverstone, Germany and Hungary.
The Silverstone squad are now fifth in the Constructors' Championship, just one point ahead of McLaren, and Perez feels the team need to regain their form after the break.
"We are losing ground," the 24-year-old said. "Williams seems to have made a step forward and also Ferrari, so at the moment we are a bit far off. There are good races coming up for us, like Monza and Spa, so we have a good opportunity.
"We have to make a step forward. We know we are not strong enough and we have been very lucky to finish in the places we have been finishing lately. We have to bring some upgrades to the car.
"We are lacking quite a lot of rear-end on the car and the operating window is pretty small. We have improved the car but obviously not enough and a lot of teams have caught us up quickly."