Nick Heidfeld admits Renault's season hinges on the major update package that they will introduce at the Belgian Grand Prix.
It has been a struggle for the team since Vitaly Petrov secured a fifth-place finish at the Canadian Grand Prix in the middle of June. They accumulated only six points in the next four races on European soil. This is in stark contrast to the magnificent early-season form which saw them claim back-to-back podiums during the opening two races in Australia and Malaysia.
Heidfeld, who was forced to retire from Sunday's Hungarian Grand Prix after his car caught fire, admits they will be in a spot of bother if the upgrades - which include new wings, bodywork and a floor update - don't work at Spa-Francorchamp.
"If it doesn't work, then we are in trouble. Let's hope for the best," he told Autosport.
"I feel it finally has to work because we have been saying for some races now that we understand the problem, and that we have moved forward. This will be the first time that we really have something big.
"Since we found out our problems we have made some small things. But we have made some big improvements in the wind tunnel now, and it was not that easy to bring all the parts to the circuit yet. So Spa is a very important place for us to go in the right direction."