Nico Rosberg said he is optimistic of a strong result for Mercedes in the Turkish Grand Prix after emerging as the closest rival to Jenson Button in Friday practice.

Having been second quickest during the wet session in the morning, Rosberg repeated the feat during the afternoon to end the dry running less than a tenth of a second away from Button's quickest lap.

On the back of a strong performance in China, where he led briefly before being forced to conserve fuel, the practice pace leaves Rosberg optimist about the remainder of the weekend with the German admitting he had been surprised by the performance of the Pirelli tyres around the challenging circuit.

"We have made a decent start to the weekend and I am optimistic for tomorrow," he said. "We had a productive afternoon and tried a lot of things with the car. I didn't have too many problems with the tyres on the long run and I was quite surprised by the grip levels, which were higher than I expected. The wet tyres had a lot of grip this morning too. I'm happy with what we learned and expecting a very interesting time tomorrow and on Sunday."

Team-mate Michael Schumacher meanwhile ended the day with the fourth quickest time despite a number of incidents on track - which included three separate spins at turn eleven.

"We had quite a positive Friday, and it was especially good that we were able to test both wet and dry tyres," he said. "I hadn't really driven the wets so I'm pleased that I finally had some opportunity to use them. Also, my sessions were quite eventful with three spins in turn eleven.

"All in all, our car confirmed the performance improvement from China, so we can look forward to the rest of the weekend. We still have some questions relating to the set-up but I am confident we will sort them out tomorrow."