Paul di Resta fears he is ill-prepared for qualifying for Force India's most important race of the year after a costly puncture in Friday practice for the Indian Grand Prix.
The problem prevented di Resta from trying the soft tyres on a heavy fuel load. The Scot was 11th fastest at the end of the day.
"It was not an easy session for me," he said. "The balance is still not perfect and we need to work hard tonight to try and improve that before final practice.
"The main issue of the day was the puncture I picked up halfway through FP2 because I missed out on my high-fuel run on the soft tires. Also, it was hard to get a clean lap during my low fuel run because the track was so busy.
"We've got data with the other car but it would have been helpful to have run more laps and got a proper feel for the soft."
Although di Resta had a troubled day, Force India's chief engineer Jakob Andreasen said the team had still managed to complete its program with Nico Hulkenberg, who was eighth fastest.
"Fortunately we got all the data we needed with Nico's program, but it certainly put Paul on the back foot," said Andreasen.