Nico Rosberg enjoying the "challenge" of teammate Lewis Hamilton

Nico Rosberg is confident ahead of the German Grand Prix after he clocked the fastest time in practice on Friday.

The 29-year-old edged ahead of teammate Lewis Hamilton in practice and insists that he is enjoying the challenge as the pair battle for the drivers' championship title.

Rosberg told reporters: "I go to every race with the belief in my head that I can win,

"I am here to win and believe I can if I put things together. It's always a challenge against Lewis".

Rosberg topped the practice charts on Friday, while Hamilton followed his teammate ahead of Fernando Alonso and Daniel Ricciardo.