Having wrapped up the title with three bonus points in qualifying earlier on Sunday morning, Preining led nearly the entirety of the race from pole position to complete a perfect weekend at the 4.5km circuit.
Much like Saturday, the Manthey EMA driver made a perfect start to lead the field into Turn 1, even as SSR Performance’s Mirko Bortolotti and Schubert BMW’s Sheldon van der Linde kept the pressure up on him.
On lap three, the safety car was deployed when Christian Engelhart crashed his Grasser Lamborghini at the entry to the hairpin after making contact with the Project 1 BMW of Marco Wittmann.
This neutralised the field and gave Bortolotti and van der Linde a sniff of the lead, but Preining managed to dissipate the threat from the duo to maintain the status quo at the front.
Van der Linde was the first of the trio to pit on lap 14, with Bortolotti and then Preining following the South African on the next two tours.
Preining’s lead stood at under a second before the pitstop cycle but he rejoined the track with his advantage over Bortolotti doubled, as van der Linde lost a few positions on cold tyres.
This should have given Preining a clear track in front of him, but Rene Rast threw a spanner in the works by pitting on lap 18 and taking the lead of the race with the overcut.
However, the Schubert BMW driver’s celebrations were short-lived as he struggled on cold tyres and slumped to fourth on his outlap, re-establishing Preining’s advantage.
In the final laps of the race, Bortolotti picked up his pace and put up a fight against Preining, bringing the gap between the two down to under half a second.
But the factory Porsche driver managed to fend off the late attack from his Lamborghini counterpart, aided by Bortolotti running wide into the final corner on the penultimate lap, to take the chequered flag by 0.8s and end his title-winning season with a fine victory.
Three-time DTM champion Rast finished behind the leading duo in third to complete an incredible recovery from 23rd on the grid, after passing the Landgraf Mercedes of Maro Engel on the final lap.
Rast made up 10 positions on the opening lap alone and made further gains to run 11th when the safety car was deployed on lap three. With two drivers running wide in front of him at the safety car restart, Rast broke inside the top 10 and then carved his way further up the pack, with his late pitstop later putting him in a position to finish on the podium.
Engel, who reported late technical problems on his Mercedes, eventually dropped to fifth, behind the other Schubert BMW of outgoing champion van der Linde.
Sixth place went to Benhard Porsche driver Laurin Heinrich, while HRT Mercedes’ Luca Stolz could only manage seventh after starting third on the grid.
He was followed by the Winward Mercedes of Lucas Auer and the top Abt Audi of Ricardo Feller.
Wittmann dragged his hobbled Project 1 BMW to 10th.
Grasser’s Alessio Deledda and Toksport WRT’s Tim Heinemann joined Engelhart in the list of retirees.
Race results: