The 25 points Muller gained for winning were enough for him to overhaul Loeb, as the World Rally legend ended his spell in the WTCC with a second fourth-place finish of the evening.
Polesitter John Filippi appeared to creep away from the line early at the start, and with front row partner Tom Coronel forced to start from the pits due to an oil leak, he held his lead into Turn 1 as Muller was promoted into second ahead of Ma Qing Hua.
The safety car made an appearance shortly afterwards, however, when Nicky Catsburg, Stefano D'Aste and Tom Chilton got together on the exit of Turn 5.
Chilton was able to continue but the remaining two retired on the spot, with the attempted recovery of their cars requiring four safety car laps before they were eventually left out of harm's way.
Muller had a good run on Filippi on the restart and was halfway up the inside of the Chevrolet on the entrance to Turn 1 before the pair touched.
Filippi was sent rotating, while Muller did well to hang on to his sideways Citroen and continued in the lead.
That spelt bad news for Loeb, with Filippi's delay - compounded by a drive-through penalty shortly afterwards for his false start - setting Muller on course to outscore Loeb by enough to reverse the pair in the championship.
Loeb pressed Norbert Michelisz for third - the Honda driver himself needing to finish ahead of Mehdi Bennani to take the Yokohama Drivers' Trophy title - but couldn't draw close enough to force an opening as second place in the standings appeared to be slipping from his clutches.
Muller, by contrast, eased away from Ma in his Citroen C-Elysee in the closing stages to win by 5.264 seconds, with his sixth victory of the season sealing the runner-up spot.
Third secured Michelisz's second Independents' crown, the Hungarian holding off Loeb by almost a second over the line to claim a sixth podium of 2015, while Bennani in the satellite Citroen came home fifth.
Hugo Valente was sixth ahead of a spritely Gabriele Tarquini, while Jose Maria Lopez ended his second championship-winning campaign in eighth, with Tiago Monteiro and Lada's Nicolas Lapierre completing the top 10.
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