Oschersleben DTM: Augusto Farfus heads all-BMW top four on Friday

As the series returns to Germany following its three international events, performance weights are again in BMW's favour, with its two heaviest drivers 30kg lighter than the top Audi and Mercedes runners.

Maxime Martin led the way for the bulk of the 45-minute session, with a 1m21.220s lap that was just 0.016 seconds ahead of Mercedes F1 reserve Pascal Wehrlein entering the final seven minutes.

Martin eventually finished the session fourth, after da Costa and then Farfus moved to the top of the timesheets and Tom Blomqvist slotted into third in the closing stages.

In the end, Farfus' 1m21.007s was 0.008s clear of Costa, with Blomqvist within 0.062s of top spot.

Wehrlein finished the session in fifth, ahead of stablemates Paul di Resta and Christian Vietoris.

The 2014 Oschersleben winner, Vietoris caused the session's only red flag when he went off at Turn 1 inside the first 10 minutes.

Timo Glock and Marco Wittmann made it six BMWs inside the top nine, ahead of Mercedes' Gary Paffett.

Next was the best of the Audi runners, Edoardo Mortara in 11th, with fellow championship contenders Jamie Green 14th and Mattias Ekstrom 17th.

Returning after his one-event suspension for the 'push him out' row, Timo Scheider was 19th fastest.

FIRST PRACTICE RESULTS: