Rosberg: Tyre issues a hindrance

Although Mercedes GP has shown strong form in qualifying, and its good straight-line speed should be useful in Montreal, its form in races has suffered because the car is too hard on its tyres.

Rosberg says that the tyre issue is now the key concern for the team - and the high degradation expected in Canada will be a big test for the outfit.

"Our car just destroys the tyres in the race," said Rosberg before first practice, where he was quickest. "It has generally been a bit of an issue this year.

"Even in Malaysia and Istanbul, we qualified third and then really struggled with rear tyres in the race. So it has been a general problem.

"In Monaco we suffered very, very badly. There were also some circumstances that didn't go perfectly, so all of it came together and it was a very bad race for us.

"This is why it is going to be important for us here because this is a track that is very difficult with rear tyres. It will be important that we make some changes so we don't get similar problems, and we improve the situation."

When asked to respond to Jenson Button's suggestions that Mercedes GP could be pace-setters this weekend, Rosberg said: "We need to see if we can sort out the race. The speed in qualifying is going to be okay for us I think. I am pretty sure, but in the race we need to see what we can do."

Although Mercedes GP has not delivered on its promising finish to pre-season testing, Rosberg still believes that the team can achieve some positive things this year.

"The targets are still there - we want to move up and get closer. We have seen glimpses of potential in the car - like in Istanbul qualifying, or the Shanghai race that we could have won.

"The potential is still there, we just need to find our way and make some good developments in the future. The developments haven't worked out so well, or maybe they have and we haven't seen them as we have had other problems or whatever.

"It is just a matter of digging away and it hasn't been ideal there. We are pushing very hard to progress in the next few races."