Marussia's Timo Glock has admitted he doesn't know why he is currently struggling so much with the MR01.

The German finished behind his rookie team-mate Charles Pic for the second race in succession in Hungary, and while the Banbury-based outfit believes it is making 'clear strides' [see separate story - HERE], Glock is not at all happy.

"Another race to forget for me, a bit like Hockenheim. I had no pace and no balance in the car from the beginning on," the 30-year-old lamented.

"Despite this I was still quicker in the first two laps but then experienced the rear end instability again. I lost the car suddenly under braking and couldn't catch it. I spun and then I was behind the HRTs and struggled massively again with the balance. I don't know what the problem is at the moment, but I think it is a good time for the break.

"My thanks to the team for the hard work in trying to resolve my problems with the car and I wish them a good holiday.

"I hope that we can all come back and enjoy a stronger second half of the season together," he added.