Michael Schumacher has admitted that it is unclear where Mercedes stand in this weekend's Singapore Grand Prix.
The German driver finished in 11th place in the second practice session.
"We had two productive sessions today, however I have not yet understood the real picture", he said.
"We will definitely need to have a good look at the data this evening and extract the true performances shown."
Schumacher also revealed that a problem on his W03 brought his session to an early halt.
We were running the new parts today and the car felt reasonable, although at the end of the second session, we had a little brake issue and had to stop. Now we will have to work hard in front of our computers to find out what our chances will be this weekend".