Nico Rosberg says Mercedes has addressed Montreal problem

Mercedes was hunting a sixth consecutive F1 one-two finish in Montreal 12 months ago before battery pack problems intervened.

The kinetic energy recover system (ERS-K) had failed and had a knock-on effect on the rear brakes. Lewis Hamilton retired because of the issue, while Rosberg salvaged second.

"We had electric motor problems or battery pack problems," said Rosberg. "They were overheating so that shut down.

"Then because you don't have any harvesting during braking on the rear you need to compensate and use the rear brakes more and as a result we had brake problems.

"The initial problem was the electric pack overheating and we have sorted that for this year because this is the most challenging track for that.

"Why? Probably because the straights are the longest here and you are using the most power for long distances, maybe that's why its overheating here the most.

"But we should have that under control."

Rosberg believes the main technical headache for teams in Canada this year will be the same tyre warm-up problems that were prevalent with the super-soft and soft in Monaco.

"Tyre warm-up will be an issue here as well," said the German.

"The super-soft is a bit harder also than last year's and that makes it a little more challenging than last year in qualifying so it will be on the edge.

"The temperature is not supposed to be too hot so let's see. It is going to be a challenge."