Formula One: Rosberg tops final practice from Hamilton

HOCKENHEIM, Germany (AFP) - Nico Rosberg topped Saturday morning's third and final free practice ahead of Mercedes team-mate Lewis Hamilton by just 0.057 seconds to complete a clean sweep of all three sessions ahead of this weekend's German Grand Prix.

The 31-year-old German produced a best lap of one minute and 15.738 seconds on a dry, warm and sunlit morning at Hockenheim where the two Mercedes men continued their domination.

Hamilton's session was upset by an investigation into an "unsafe release" when he came out of the pits ahead of Frenchman Romain Grosjean, who had to stop his Haas to allow the defending champion out.

The stewards launched an investigation into the release, which may result in a penalty for Mercedes ahead of qualifying, which is due to take place later on Saturday.

Australian Daniel Ricciardo, in his 100th Grand Prix, was third fastest for Red Bull ahead of Finn Kimi Raikkonen and his Ferrari team-mate Sebastian Vettel.

Dutch teenager Max Verstappen was sixth for Red Bull ahead of Valtteri Bottas of Williams, two-time world champion Fernando Alonso, who turned 35 on Saturday, in his McLaren and German Nico Hulkenberg, 10th for Force India.

The top three drivers were separated by less than one-tenth of a second and the top nine by less than a full second, indicating that a highly competitive qualifying is in prospect.