Rubens Barrichello says he is worried his Ferrari team might be beaten next season because of advances made by their rivals' tyre company.
Barrichello is worried that Michelin advances will leave Ferrari trailing
He fears Michelin, which supplies McLaren, Williams and Renault, will come up with a better tyre than the Bridgestones used by Ferrari.
"The improvement Michelin made in 2003 was impressive," he told Italian newspaper Gazzetta dello Sport.
"If they make another one like that next year, we will have to catch up."
Michelin is known already to have made significant steps forward in winter testing, a fact that has not gone unnoticed at Ferrari.
The world champions tested alongside the new McLaren in Spain earlier this month and were left lagging well behind on pace.
Barrichello believes Ferrari will be pushed even harder next year by all the teams who challenged them in 2003.
"I'm under no illusions," he said.
"It will be a hard battle against McLaren, Williams and Renault, and who knows if some other team will manage to
come out with a competitive car that can fight for the top spots?
"Obviously I hope that the end of the season will be like it was this year, with Ferrari winning."