It was a difficult opening day for Nico Rosberg, the Mercedes driver disappointed with his performance having hoped for more ahead of the weekend.

"Not a very promising day for us," conceded a dejected Rosberg. "I expected to be stronger.

"We tried some major things, especially on my car, just to see if we could bring the car in to a different window mechanically, but it didn't really work out."

Although fourth fastest in the morning the German driver finished the day in eleventh after rain interrupted the afternoon session. Indeed the difficult conditions caught out Michael Schumacher in the other Mercedes, seeing him skid gently into the tyre barriers as the rain worsened.

"It was very strange out there," Rosberg explained. "There were some places that were completely dry on the track and some places where there were even rivers."

"The first sector in general was dry and then the middle to last sector was the difficult part," agreed Timo Glock. "It's quite difficult here because of the water running across the track in some areas which was quite strange in turn eleven for example, you lost the car quite quickly and Michael lost it in turn twelve."

"It didn't look like it would be that long," Glock continued. "I thought it would be only in the middle sector some rain drops but then suddenly the whole track was a bit wet.

Fellow German Sebastian Vettel also endured a frustrating day. "The weather caught us out like everyone," he said. "We didn't get a crack on the soft tyres therefore it's difficult to compare in terms of competitiveness but I think it was a normal Friday.

"There's still a lot of room for improvement for us things we need to do a little bit better for the rest of the weekend," he added. "It looks to be quite tight. It's a short lap so I think it will be extremely tight in qualifying if it's dry."

Tomorrow's forecast is expected to be much the same as today; mostly dry and hot, with possible showers later in the afternoon.

Check out our Friday gallery, here.