Nico Rosberg was 0.601 seconds faster than Mercedes team-mate Lewis Hamilton in third practice for the 2014 Formula 1 German Grand Prix.
Fernando Alonso was third quickest for Ferrari.
Both Mercedes went out on simulated qualifying runs in the closing minutes but Hamilton's lap was scrappier than Rosberg's.
Most teams focused on longer runs with higher fuel loads for the majority of the session, before sending their drivers out for qualifying-style efforts on the super-soft tyres in the final 10 minutes.
Williams was chasing laptime early in the session, which put Valtteri Bottas and Felipe Massa at the top of the timesheets for the first half hour until Kimi Raikkonen, the first driver to go out on the super-soft tyres, usurped them.
Times then tumbled in the final minutes as Mercedes returned to its customary 1-2 position.
Fernando Alonso had a spin at Turn 8 after overshooting the apex and running wide over the exit kerb, but his super-soft run was flawlessly committed and he closed out the session third fastest, 0.605s off Rosberg's benchmark.
Alonso's Ferrari team-mate Raikkonen did not improve on the 1m18.842s he set on his first super-soft run, and was eighth quickest overall.
Bottas had outpaced Massa on the longer runs, but in qualifying trim the Brazilian had the edge over his team-mate and they ended the session fourth and fifth just off Alonso's pace.
It was Jenson Button's turn to test McLaren's new rear wing, but he struggled with locking brakes and ended the session 0.8s slower than team-mate Kevin Magnussen, who was sixth fastest - seven places ahead of the Briton.
Daniel Ricciardo and Sebastian Vettel were fighting their cars throughout and the Red Bull drivers could do no better than seventh and ninth.
Pos Driver Team Time Gap Laps
1. Nico Rosberg Mercedes 1m17.779s 24
2. Lewis Hamilton Mercedes 1m18.380s +0.601s 20
3. Fernando Alonso Ferrari 1m18.384s +0.605s 11
4. Felipe Massa Williams-Mercedes 1m18.575s +0.796s 18
5. Valtteri Bottas Williams-Mercedes 1m18.611s +0.832s 19
6. Kevin Magnussen McLaren-Mercedes 1m18.756s +0.977s 16
7. Daniel Ricciardo Red Bull-Renault 1m18.769s +0.990s 13
8. Kimi Raikkonen Ferrari 1m18.842s +1.063s 8
9. Sebastian Vettel Red Bull-Renault 1m18.890s +1.111s 17
10. Nico Hulkenberg Force India-Mercedes 1m19.127s +1.348s 19
11. Daniil Kvyat Toro Rosso-Renault 1m19.131s +1.352s 19
12. Jean-Eric Vergne Toro Rosso-Renault 1m19.470s +1.691s 20
13. Jenson Button McLaren-Mercedes 1m19.489s +1.710s 15
14. Sergio Perez Force India-Mercedes 1m19.505s +1.726s 21
15. Esteban Gutierrez Sauber-Ferrari 1m19.601s +1.822s 23
16. Romain Grosjean Lotus-Renault 1m20.078s +2.299s 23
17. Jules Bianchi Marussia-Ferrari 1m20.198s +2.419s 21
18. Pastor Maldonado Lotus-Renault 1m20.466s +2.687s 19
19. Adrian Sutil Sauber-Ferrari 1m20.844s +3.065s 6
20. Kamui Kobayashi Caterham-Renault 1m21.018s +3.239s 21
21. Marcus Ericsson Caterham-Renault 1m23.077s +5.298s 14
22. Max Chilton Marussia-Ferrari 1m23.449s +5.670s 7