Robert Wickens ended BMW's domination of the final DTM pre-season test at Hockenheim as he topped the times for Mercedes on Thursday.
The Canadian was the only driver to break the 1m33s barrier with a best time of 1m32.845s, though that was still 0.8s shy of Marco Wittmann's Tuesday benchmark.
Wickens' effort came in the morning session but was easily good enough to retain top spot despite several drivers improving in the afternoon.
Audi's reigning champion Mike Rockenfeller finished second, just under three-tenths back, while Wickens' HWA Mercedes team-mate Gary Paffett completed the Three-Pointed Star's testing resurgence with the third fastest time.
The Audi RS5s of Abt driver Adrien Tambay and Rosberg's Jamie Green, the latter having gone second quickest in the morning, completed the top five, while the best of the BMW M4s was Augusto Farfus' RBM machine in sixth.
Bruno Spengler was the busiest driver as the second test drew to a close, racking up 174 laps in his Schnitzer M4 en route to seventh quickest time. The 2012 champion was fractionally faster than RMG BMW driver Maxime Martin and new World Rallycross Championship team founder Mattias Ekstrom in the second Abt RS5.
Single-seater converts Vitaly Petrov and Antonio Felix da Costa completed the order for Mercedes and BMW respectively.
Pos Driver Team/Car Time Gap
1. Robert Wickens HWA Mercedes 1m32.845s
2. Mike Rockenfeller Phoenix Audi 1m33.105s +0.260s
3. Gary Paffett HWA Mercedes 1m33.180s +0.335s
4. Adrien Tambay Abt Audi 1m33.287s +0.442s
5. Jamie Green Rosberg Audi 1m33.319s +0.474s
6. Augusto Farfus RBM BMW 1m33.505s +0.660s
7. Bruno Spengler Schnitzer BMW 1m33.617s +0.772s
8. Maxime Martin RMG BMW 1m33.747s +0.902s
9. Mattias Ekstrom Abt Audi 1m33.753s +0.908s
10. Vitaly Petrov Mucke Mercedes 1m33.894s +1.049s
11. Antonio Felix da Costa MTEK BMW 1m34.096s +1.251s