Kimi Raikkonen says his world championship bid has been damaged by McLaren's decision not to race in Indianapolis almost a fortnight ago.
The Finn arrives at Magny-Cours for this weekend's French Grand Prix trailing Renault's championship leader Fernando Alonso by 22 points with ten races remaining.
All the Michelin-supplied teams opted not to race in the United States due to safety fears - Raikkonen needed all McLaren's powers of persuasion to keep him from starting a race which he was favourite to win.
Raikkonen, who flew to New York while the race was still underway, said: "It was disappointing but, in the end, there was nothing that could be done. I listened to what people said should be done.
"Every race we don't race is not going to help us because we need as many races as possible to try to catch up the Renaults and Alonso but that is the situation." Raikkonen believes his McLaren will again be the car to beat this weekend, saying: "The car should be good. We have some new parts and a new engine, so I am looking forward to it."
McLaren and home heroes Renault still head both championships after their stunning start to the season, but recent races suggest Renault's performance advantage has been eroded by McLaren.
Alonso is optimistic his car will be a match for Raikkonen's and expects Renault's home race to be a happy one.
The Spaniard said: " Indianapolis was a difficult weekend for everybody and not a fantastic feeling when you have to come into the pits. But the situation was like that.
"It's true we lost ten points but always, when you arrive at the grand prix, you are thinking of scoring points. We need to race and score points, as that is the main thing from a weekend. I hope this year we can be competitive here. The car is performing well at all circuits and perhaps here even more so.
"Obviously, it's the home grand prix, so a lot of Renault people will be here and a lot of important people from Renault.
"We are all very excited and I am optimistic. We arrive at a very good moment leading both championships, we arrive at a perfect point this weekend."
Alonso and Raikkonen are battling to steal the crown from Ferrari's Michael Schumacher who was effectively given a free ten points at Indianapolis and trails Alonso by only 25, despite a poor first half of the season.
