Mike Rockenfeller led an Audi lock-out of the top six places in a wet DTM free practice session at Hockenheim.

The Audi driver had a couple of spells at the top in the final half an hour of the session, as conditions improved. He traded places with Timo Scheider for a little while, before securing first place by 0.001 seconds with 12 minutes to go.

There was a flurry of activity in the last five minutes as all of the cars that had not suffered incidents went out on track, but a return of the rain prevented anyone else from improving. That left Scheider in second place ahead of Martin Tomcyk, who earned a five-place grid drop for Sunday's race after he set a personal best sector time under yellow flags.

Miguel Molina was next up in fourth. The Spaniard had been on course to go fastest just after Rockenfeller set his best lap, but he made a mistake in the final sector.

Behind Mattias Ekstrom and Oliver Jarvis, Gary Paffett was the best of the Mercedes in seventh, as most of the C-class drivers missed the best of the conditions.

But the main interest at that end of the pitlane surrounded championship leader Bruno Spengler, who crashed with half an hour to go at the penultimate corner.

The Canadian had been in the top 10 at the time, but even then he was more than half a second adrift of his closest title challenger Paul di Resta, who had shone in the worst of the conditions early on.

Spengler was pulled out of the tyre wall and returned to the pits with only minor damage, but he was unable to get back on track before the end of the session.

Pos  Driver             Car       Time       Gap
 1.  Mike Rockenfeller  Audi      1m36.999s
 2.  Timo Scheider      Audi      1m37.000s  + 0.001s
 3.  Martin Tomczyk     Audi      1m37.060s  + 0.061s
 4.  Miguel Molina      Audi      1m37.523s  + 0.524s
 5.  Mattias Ekstrom    Audi      1m37.914s  + 0.915s
 6.  Oliver Jarvis      Audi      1m37.956s  + 0.957s
 7.  Gary Paffett       Mercedes  1m37.999s  + 1.000s
 8.  Maro Engel         Mercedes  1m38.247s  + 1.248s
 9.  Paul di Resta      Mercedes  1m38.337s  + 1.338s
10.  Ralf Schumacher    Mercedes  1m38.517s  + 1.518s
11.  Markus Winkelhock  Audi      1m38.520s  + 1.521s
12.  Katherine Legge    Audi      1m38.527s  + 1.528s
13.  Jamie Green        Mercedes  1m38.705s  + 1.706s
14.  David Coulthard    Mercedes  1m38.960s  + 1.961s
15.  Bruno Spengler     Mercedes  1m39.020s  + 2.021s
16.  Alexandre Premat   Audi      1m39.208s  + 2.209s
17.  Susie Stoddart     Mercedes  1m39.472s  + 2.473s
18.  Cong Fu Cheng      Mercedes  1m40.882s  + 3.883s