Invicta Virtuosi driver Doohan put in an assured performance to take the final win of the season as F2 waved farewell to the current specification chassis.
But the Alpine Formula 1 reserve's uneventful run to a third feature win of the year was shaded by a thrilling battle for championship honours between Pourchaire (ART) and Prema rival Frederik Vesti.
After a charging victory in Saturday's sprint race, Vesti fell painfully short of making back the 16-point deficit with which he had been faced, crossing the line in third after starting ninth.
Pourchaire, who had started 14th, finished fifth with a stout three-lap defence when battling Vesti a period that can be pinpointed as the moment he secured his title.
The opening lap was a relatively calm affair in F2 terms, with the only incident of note being Ayumu Iwasa making use of the runoff at the Turn 6-7 chicane and gaining fourth from Zane Maloney. One lap later, he handed the position back at the same place but immediately retook the place, meaning the incident was noted by race control, although no further action was taken.
Prema put Vesti on the alternate strategy, running the medium tyres in the opening stint and going long while those ahead fitted softs. Conversely, Pourchaire started on the red-walled softer option.
At the end of lap six of 33, Pourchaire pitted for mediums, removing the risk of a poorly timed safety car interruption ruining his charge.
Neither championship protagonist had made significant progress in the early laps with Vesti finding himself stuck behind Isack Hadjar (Hitech). But once the Frenchman pitted at the end of lap eight, he could get the hammer down, with his engineers urging him on and demanding the next 10 laps to be “like one big quali lap”.
Race leader Doohan pitted for mediums at the end of lap nine, returning to the track in 12th spot.
Source: Autosport