BERLIN  (AFP) - Nico Rosberg topped the 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.