The man, in his fifties, was taken by helicopter to Aberdeen Royal Infirmary after the incident at the Granite City Rally in Durris Forest, outside the city, on Saturday.
He was left with “life-threatening” injuries to his leg and pelvis after the rally car came off a forest track and collided with four male spectators.
The accident happened as spectators rushed to aid the Nissan Micra driven by Rachel Medich, after it veered into a ditch.
The Peugeot of Simon Frazer Hay then went off at the same spot minutes later hitting a number of them, the Aberdeen and District Motor club said
Three other men were taken to hospital by ambulance at around 11:20am. One of them received minor injuries, and two had “serious injuries which are described as not life-threatening”.
One was a competitor in the Scottish Rally Championship, the Aberdeen and District Motor Club said.