Romain Grosjean has admitted that both he and Lotus will find it difficult to maintain their recent return to form at this weekend's Canadian Grand Prix.

The Frenchman has scored points in each of the last two races, at Barcelona and Monaco, after a struggle over the first four rounds of the season.

However, Grosjean believes that the characteristics of the Gilles Villeneuve Circuit may not suit the Enstone-based outfit's 2014 car.

He told reporters: "You never know until you start but, on paper, it's going to be very difficult against the 'Mercedes four'. You are always trying to get rid of some downforce here, but then it is tricky in the corners. On paper, that looks like a big advantage for Mercedes.

"What we have seen in Barcelona was not a one-day shot. I think it was more relevant of the car's performance. Yes, there are still quite a lot of places where we can improve and, if we do so, we should be even more consistent."

Grosjean's teammate Pastor Maldonado is yet to score a point for Lotus since his winter move from Williams.