Rosberg says Mercedes closer to rivals

But Rosberg conceded tyre management is still a problem for the German squad.

"It was okay, we've made a step in the right direction," said Rosberg, who posted the quickest time in the morning practice session on Friday.

"We've made some progress, especially with all the new parts that have come - but still have a little bit of a problem with making the tyres work, especially on this track today, so it's still not ideal.

"But we are definitely a step closer to the front which has been nice, with high fuel, we were very quick today - so it's looking like a better weekend.

"It is difficult to compare from one track to another, but definitely feels like we have a stronger car," added the German, fourth fastest in the afternoon.

Rosberg is optimistic Mercedes can still catch the front-running cars if it continues with its rate of development.

"Yeah, I think everybody has done a really good job back at the factory because it is a nice step for us and it is not easy to make them work and reliable and all these things, but the guys have worked well during the day to make things work out well, and it is looking good," he said.