Heidfeld – I’m not Kubica’s no.2
Kubica is narrowly leading the drivers' world championship while 31-year-old Heidfeld lags 14 points behind.
But the German told Sport Bild: "The situation has not in itself changed anything. There has not been and there still is no number one or number two status.
"Robert is driving a strong season," Heidfeld explained, "but it pays to have two strong drivers, in case one has problems, and also so that your teammate has a high benchmark."
Heidfeld said he is getting to the bottom of his current troubles with the 2008 car.
"Yes and no," he explained. "The last race was not bad — my problem is that I cannot bring the car far enough forwards in qualifying.
"The numbers in the race are still very good," Heidfeld said.