Edoardo Mortara resisted intense race-long pressure from Gary Paffett and Martin Tomczyk to take his first DTM victory at Spielberg.
The Rosberg Audi driver started from pole and was only briefly headed during the 47-lap race, eventually beating Tomczyk's RMG BMW by just over a second with HWA Mercedes driver Paffett in third.
Paffett's chance to win came after Mortara's final stop on lap 30. Having stopped for fresh rubber a lap earlier, the British driver was quicker on the run down to the Remus Kurve than Mortara as the Italian exited the pits. As he moved right to pass, Mortara defended, pushing the Mercedes' right wheels onto the grass momentarily, but keeping the advantage.
Tomczyk, third before the stops, exited in the lead when he pitted a lap later, but Mortara's greater momentum out of the first corner carried him past the champion into Remus.
Tomczyk came back at Mortara into the following turn, clipping the rear of the Audi under braking and pushing him wide, but the German's own lost pace meant that instead of pushing for the lead, he was forced to defend second into the next turn from Paffett instead.
That was as close as the battle got, with Mortara winning from Tomczyk and Paffett, who increased his championship lead to 36 points. Mattias Ekstrom's Abt Audi and Jamie Green's HWA Mercedes completed the top five, less than 5sec behind the winner.
Timo Scheider put in a tremendous drive to finish sixth. After dropping to the tail of the field after contact with Augusto Farfus put him into the Goldschlosser Kurve gravel trap, the former champion carved through the field to take his best finish of the year.
Phoenix Audi driver Mike Rockenfeller passed Joey Hand's RMG BMW for seventh at the final corner with just three laps left and Mortara's team-mate Filipe Albuquerque also overtook the American seconds later to steal eighth. Hand still scored his first DTM points in ninth while fellow BMW man Farfus completed the top 10.
Title contender Bruno Spengler suffered from poor speed for the first two thirds of the race thanks to damage sustained on a chaotic opening lap. The Schnitzer driver later retired as a result.
Eliminated as a result of a chain reaction that began when Adrien Tambay's Abt Audi was forced onto the grass at Remus on the opening lap were the Frenchman himself, Dirk Werner, Andy Priaulx and Christian Vietoris.
Results - 47 laps:
Pos Driver Team/Car Time/Gap
1. Edoardo Mortara Rosberg Audi 1h12m30.277s
2. Martin Tomczyk RMG BMW + 1.068s
3. Gary Paffett HWA Mercedes + 2.142s
4. Mattias Ekstrom Abt Audi + 2.769s
5. Jamie Green HWA Mercedes + 5.406s
6. Timo Scheider Abt Audi + 35.351s
7. Mike Rockenfeller Phoenix Audi + 37.260s
8. Filipe Albuquerque Rosberg Audi + 38.062s
9. Joey Hand RMG BMW + 39.419s
10. Augusto Farfus RBM BMW + 39.904s
11. Ralf Schumacher HWA Mercedes + 43.567s
12. Roberto Merhi Persson Mercedes + 50.339s
13. Robert Wickens Mucke Mercedes + 1m05.670s
14. Susie Wolff Persson Mercedes + 1m06.161s
15. Rahel Frey Abt Audi + 1m06.988s
Bruno Spengler Schnitzer BMW 33 laps
David Coulthard Mucke Mercedes 22 laps
Miguel Molina Phoenix Audi 17 laps
Andy Priaulx RBM BMW 1 lap
Dirk Werner Schnitzer BMW 1 lap
Christian Vietoris HWA Mercedes 0 laps
Adrien Tambay Abt Audi 0 laps