SILVERTSONE, England (AP) -- Nico Rosberg posted the fastest time ahead of championship-leading teammate Lewis Hamilton in the first practice session of the British Grand Prix on Friday.
The German driver missed much of the session after going off due to a loss of hydraulic power at Silverstone.
He was 0.07 seconds faster than Hamilton, who is chasing his third victory at his home race, and has a 10-point lead over Rosberg after eight races.
Mercedes team boss Toto Wolff says "maybe it was just software electronics" at fault for Rosberg's problems.
Max Verstappen of Toro Rosso was third quickest, followed by Kimi Raikkonen of Ferrari.