Nico Rosberg went fastest for Mercedes in first practice for the 2014 Formula 1 German Grand Prix at Hockenheim.
Rosberg went 0.065s quicker than team-mate Lewis Hamilton. Ferrari's Fernando Alonso was best of the rest, 0.292s off Rosberg's pace.
The Mercedes pairing were among many to explore the track limits frequently as the drivers adjusted to life without the FRIC suspension systems that all teams have removed in advance of the weekend.
Sebastian Vettel was fastest on 1m20.295s in the busy first half-hour of session as several drivers made use of the extra set of soft tyres that have to be handed back to Pirelli at the 30-minute mark.
He improved that time during a multi-lap run later in the session, but by that time both Jenson Button and Daniel Ricciardo had gone even faster.
At that point Mercedes finally showed its hand as first Rosberg, then Hamilton, went half a second faster than their rivals, a gap only Alonso could partially bridge - and then only with a committed lap.
Hamilton was quickest of all in the first two sectors, but could not unite the two over the course of one lap, finishing on 1m19.196s to Rosberg's 1m19.131s.
Ferrari used the early part of the session to evaluate aero characteristics of Alonso's rear wing with flow-vis paint, but its programme was set back when Kimi Raikkonen had a water pump failure that took half an hour to resolve.
Raikkonen returned to the track but, in spite of completing a respectable number of laps, set a best time of 1m20.210 that was only eighth fastest overall.
McLaren sported a fresh look, with a new rear wing design featuring sophisticated detailing around the endplates, and a new race engineer for Jenson Button: Olympic rowing medallist Tom Stallard.
They had a reasonably encouraging session, Button completing 24 laps and Kevin Magnussen 32, finishing fifth and seventh quickest.
Williams tester Susie Wolff enjoyed a lengthier stint in the cockpit than she did at Silverstone, despite a scare in the opening minutes when her FW36 slowed with a sensor issue.
She closed out the session just two tenths of a second off the pace of Felipe Massa, well under the half-second benchmark the team had set.
There was a substantial gap between the runners at the bottom end of the timesheets as Lotus, Caterham and Marussia languished over two seconds off the pace.
Romain Grosjean had a rear wing failure that caused his DRS to stick open under braking in a high-speed section, while Max Chilton brought up the rear after a number of power unit problems.
Pos Driver Team Time Gap Laps 1. Nico Rosberg Mercedes 1m19.131s 29 2. Lewis Hamilton Mercedes 1m19.196s +0.065s 25 3. Fernando Alonso Ferrari 1m19.423s +0.292s 21 4. Daniel Ricciardo Red Bull-Renault 1m19.697s +0.566s 27 5. Jenson Button McLaren-Mercedes 1m19.833s +0.702s 24 6. Sebastian Vettel Red Bull-Renault 1m20.097s +0.966s 28 7. Kevin Magnussen McLaren-Mercedes 1m20.105s +0.974s 32 8. Kimi Raikkonen Ferrari 1m20.210s +1.079s 21 9. Daniil Kvyat Toro Rosso-Renault 1m20.337s +1.206s 28 10. Adrian Sutil Sauber-Ferrari 1m20.505s +1.374s 18 11. Felipe Massa Williams-Mercedes 1m20.542s +1.411s 19 12. Jean-Eric Vergne Toro Rosso-Renault 1m20.586s +1.455s 23 13. Nico Hulkenberg Force India-Mercedes 1m20.592s +1.461s 22 14. Sergio Perez Force India-Mercedes 1m20.598s +1.467s 24 15. Susie Wolff Williams-Mercedes 1m20.769s +1.638s 22 16. Giedo van der Garde Sauber-Ferrari 1m20.782s +1.651s 23 17. Romain Grosjean Lotus-Renault 1m21.603s +2.472s 20 18. Pastor Maldonado Lotus-Renault 1m21.854s +2.723s 30 19. Kamui Kobayashi Caterham-Renault 1m22.572s +3.441s 31 20. Jules Bianchi Marussia-Ferrari 1m22.982s +3.851s 24 21. Marcus Ericsson Caterham-Renault 1m23.256s +4.125s 35 22. Max Chilton Marussia-Ferrari 1m23.299s +4.168s 22