Fernando Alonso believes his Renault team have the edge in the constructors' race after both McLarens struggled in qualifying for the Japanese GP.
McLaren lead Renault by two points but with Alonso and the McLarens hit by a deluge in qualifying, Giancarlo Fisichella's third place could be key.
"The drivers' championship is over now," said world champion Alonso.
"But we have confidence we can win the constructors' championship too. I think we have a little advantage."
Fisichella defied the worsening rain to finish third behind Toyota's Ralf Schumacher and BAR's Jenson Button.
But torrential rain ruined any qualifying hopes of the last four drivers out - Alonso, Ferrari's Michael Schumacher and McLaren pair Kimi Raikkonen and Juan Pablo Montoya.
Raikkonen, who already had a 10-place penalty for an engine change on Friday, coasted to 17th, while Montoya aborted his flying lap completely.
Alonso, who qualified 16th, added: "The grid positions were unexpected but with one Renault and two McLarens at the back, the other Renault has to win."
Renault's director of engineering Pat Symonds said: "Our team is collectively in a better position.
"Fisico's [Fisichella] lap was truly exceptional in difficult and worsening conditions. He will be looking for a very strong performance."
McLaren boss Ron Dennis, however, believes the weather has played into the hands of Raikkonen, who will now be able to start with a heavier fuel load than his rivals.
"The engine change has actually improved Kimi's chances of winning the race," said Dennis. "His grid position would have been the same because of the rain.
"But now he has a race strategy based on having an engine change, which is a better race strategy than it would have been if he had been going for pole position."
Mercedes boss Norbert Haug has apologised to McLaren for the number of engine failures they
have suffered this year.
As well as Friday's problem, Raikkonen has suffered three other blown engines in practice this season.
Haug, whose company supplies McLaren with their powerplants, said: "We never speak about bad luck, we are just not good enough.
"We are trying to push forward and we have made good steps but it is not 100%.
"Nobody has changed engines as much as us, but we are also in the limelight and it always hits Kimi's car.
"I have to apologise to the guys but we are fully committed to it and nobody is leaning back and thinking we are almost there."
McLaren's hopes of clinching the title in Suzuka depend on them finishing first and second with Renault scoring no more than one point. Otherwise the battle will be decided in Shanghai next weekend.