Christian Vietoris put Mercedes on top as the Hungaroring DTM test continued on Wednesday.
Audi drivers had dominated the test's opening days, and did so again as Abt's Adrien Tambay set the pace on the third morning.
But in the second session Vietoris set the best lap of the week so far with a 1m37.461s.
That put him just under 0.4 seconds clear of Marco Wittmann, who headed a BMW trio ahead of Timo Glock and Augusto Farfus.
Tambay was top Audi man in sixth, behind Pascal Wehrlein's Mercedes.
The test concludes on Thursday.
Pos Driver Team/Car Time Gap 1. Christian Vietoris HWA Mercedes 1m37.461s 2. Marco Wittmann RMG BMW 1m37.837s +0.376s 3. Timo Glock MTEK BMW 1m37.861s +0.400s 4. Augusto Farfus RBM BMW 1m37.895s +0.434s 5. Pascal Wehrlein HWA Mercedes 1m38.002s +0.541s 6. Adrien Tambay Abt Audi 1m38.014s +0.553s 7. Nico Muller Rosberg Audi 1m38.069s +0.608s 8. Timo Scheider Abt Audi 1m38.167s +0.706s 9. Miguel Molina Abt Audi 1m38.187s +0.726s 10. Martin Tomczyk Schnitzer BMW 1m38.417s +0.956s 11. Robert Wickens HWA Mercedes 1m38.901s +1.440s 12. Daniel Juncadella HWA Mercedes 1m39.437s +1.976s