Nico Rosberg snatched the top spot from Mercedes team-mate Lewis Hamilton in the final seconds of British Grand Prix practice three at Silverstone.
Hamilton had established himself as the fastest man by the end of the hard-tyre runs with a 1m31.750s lap.
He looked set to improve on that when on mediums late on, but slid over the run-off at Brooklands.
While Hamilton gathered himeself up for another go, Rosberg came through with a 1m31.487s to grab first place.
Hamilton also improved on his last lap but had to settle for second on a 1m31.633s, 0.146 seconds off his team-mate.
Mercedes enjoyed a half-second cushion over the rest of the field.
Sebastian Vettel secured third with his last lap, just ahead of Red Bull team-mate Mark Webber.
Romain Grosjean was fifth for Lotus, while Toro Rosso's impressive weekend continued as Daniel Ricciardo took sixth.
The session had to be red-flagged early on after Sergio Perez's left rear tyre blew.
The incident will be a concern to Pirelli on the weekend when it introduces its new bonding process, designed to prevent delaminations.
A brief stoppage was required to remove tyre debris from the circuit.
Perez's McLaren sustained quite a lot of damage at its rear end, but was able to rejoin for the final minutes, only for the Mexican to slide off at Becketts.
Fernando Alonso also had a moment at the same spot before putting his Ferrari seventh.
Kimi Raikkonen's Lotus and the Force Indias of Adrian Sutil and Paul di Resta completed the top 10.
Home driver Jenson Button was back in 12th for McLaren.
Felipe Massa spent the final minutes parked in the Ferrari garage with an apparent problem and was only 15th.
Pos Driver Team/Car Time Gap Laps 1. Nico Rosberg Mercedes 1m31.487s 18 2. Lewis Hamilton Mercedes 1m31.633s +0.146s 20 3. Sebastian Vettel Red Bull-Renault 1m32.037s +0.550s 20 4. Mark Webber Red Bull-Renault 1m32.078s +0.591s 17 5. Romain Grosjean Lotus-Renault 1m32.391s +0.904s 18 6. Daniel Ricciardo Toro Rosso-Ferrari 1m32.440s +0.953s 19 7. Fernando Alonso Ferrari 1m32.454s +0.967s 18 8. Kimi Raikkonen Lotus-Renault 1m32.459s +0.972s 22 9. Adrian Sutil Force India-Mercedes 1m32.536s +1.049s 17 10. Paul di Resta Force India-Mercedes 1m32.571s +1.084s 17 11. Jean-Eric Vergne Toro Rosso-Ferrari 1m32.580s +1.093s 15 12. Jenson Button McLaren-Mercedes 1m32.926s +1.439s 18 13. Pastor Maldonado Williams-Renault 1m33.133s +1.646s 17 14. Nico Hulkenberg Sauber-Ferrari 1m33.225s +1.738s 16 15. Felipe Massa Ferrari 1m33.273s +1.786s 16 16. Valtteri Bottas Williams-Renault 1m33.309s +1.822s 25 17. Esteban Gutierrez Sauber-Ferrari 1m33.370s +1.883s 19 18. Sergio Perez McLaren-Mercedes 1m33.607s +2.120s 9 19. Charles Pic Caterham-Renault 1m34.971s +3.484s 18 20. Jules Bianchi Marussia-Cosworth 1m34.990s +3.503s 17 21. Max Chilton Marussia-Cosworth 1m36.694s +5.207s 16 22. Giedo van der Garde Caterham-Renault 1m37.443s +5.956s 18