Miguel Molina warmed up for his home round of the DTM by setting the pace in the opening practice session at Valencia.
The Spaniard took his old-spec Abt Audi to the top of the time sheets in 1m31.770s just 20 minutes into the session, and was never headed as temperatures increased on a dry afternoon.
Gary Paffett was Mercedes' top driver in second, 0.041sec slower than Molina. Like the Audi man, the HWA driver's best lap came inside the first half hour.
The championship's in-form driver, Mattias Ekstrom, was third for Abt in the best of the newer-spec A4s, while HWA trio Ralf Schumacher, Jamie Green and Bruno Spengler filled the next three spots on what was an unusually competitive Friday showing for the Mercedes' A team.
Abt's Timo Scheider and Persson Mercedes driver Renger van der Zande were next up, with Filipe Albuqerque ninth in his Rosberg Audi.
Martin Tomczyk, who will be crowned champion if he wins Sunday's race, completed the top 10 in his Phoenix Audi. In a typically close session, just 1.3sec separated the top 17 drivers.
Pos Driver Team/Car Time Gap
1. Miguel Molina Abt Audi 1m31.770s
2. Gary Paffett HWA Mercedes 1m31.811s +0.041s
3. Mattias Ekstrom Abt Audi 1m32.031s +0.261s
4. Ralf Schumacher HWA Mercedes 1m32.093s +0.323s
5. Jamie Green HWA Mercedes 1m32.139s +0.369s
6. Bruno Spengler HWA Mercedes 1m32.141s +0.371s
7. Timo Scheider Abt Audi 1m32.156s +0.386s
8. Renger van der Zande Persson Mercedes1m32.166s +0.396s
9. Filipe Albuquerque Rosberg Audi 1m32.307s +0.537s
10. Martin Tomczyk Phoenix Audi 1m32.312s +0.542s
11. David Coulthard Mucke Mercedes 1m32.352s +0.582s
12. Christian Vietoris Persson Mercedes1m32.364s +0.594s
13. Edoardo Mortara Rosberg Audi 1m32.472s +0.702s
14. Susie Stoddart Persson Mercedes1m32.700s +0.930s
15. Mike Rockenfeller Abt Audi 1m32.900s +1.130s
16. Oliver Jarvis Abt Audi 1m32.918s +1.148s
17. Maro Engel Mucke Mercedes 1m33.003s +1.233s
18. Rahel Frey Phoenix Audi 1m33.589s +1.819s