Nico Rosberg led the charge for Mercedes today during practice for Sunday's Canadian Grand Prix at the Circuit Gilles Villeneuve, the latest round on the F1 2010 schedule.

Rosberg, who was fourth in the opening session, improved this afternoon and finished free practice two in P3, on a 1 minute 17.151 seconds, which left him just 0.274 seconds off the ultimate pace set by Sebastian Vettel.

Speaking after completing over 50 laps, Rosberg was pretty happy with his Mercedes GP W01: "I'm generally pleased with the progress that we made today," he confirmed, "although conditions were difficult because it was very slippery out there on the track.

"We made some good set-up changes to help the car around this circuit and spent a lot of time working with the tyres to understand their performance. The soft option tyre was particularly difficult and we were struggling a little there, like many teams. But overall it was a good start and we have a lot of information to look at tonight before qualifying."

Team-mate Michael Schumacher meanwhile was less happy and he slipped back this afternoon. Indeed having been second quickest in FP1, he could only set the ninth best time in FP2.

"My sessions today were a bit mixed. In the morning, we were making progress but towards the end we carried over some issues into the second session which we could not solve," Schumacher said. "The main focus this afternoon was to get the tyres together.

"The track is pretty green with not much rubber which means the tyres are getting a hard time and everybody was struggling with graining. If it rains, the track will remain green and it will probably be difficult to hold the tyres together again, even the harder compound.

"For tomorrow, it is difficult to predict what we will be able to achieve. My feeling is that we will perform according to our expectations which is around the third quickest of the teams."

Mercedes team principal Ross Brawn summed-up: "We're reasonably happy with where we are today in terms of performance and were able to achieve some good longer runs this afternoon in preparation for the race.

"The key consideration for the weekend looks to be the tyre strategies and managing the levels of graining, particularly on the options and to a lesser extent the prime, as was evident from the struggles faced by most of the teams this afternoon. With the predicted weather conditions for the weekend, this could all change, but for now we are in a decent position and looking forward to qualifying tomorrow."