Sergio Perez believes Force India faces a fight to get in to Q3 after being unable to recognise problems with his car on the supersoft tyre.
Pirelli has supplied the soft and supersoft compound tyres for this weekend's Singapore Grand Prix, with the softest compound best for the street circuit. However, Perez says the performance of the tyre over a qualifying run drops off so dramatically it is hard to work out how the car is handling itself.
"On my single lap, there’s so much degradation on the options, it hides quite a lot of your problems," Perez said. "It’s a bit like Monaco, you don’t really notice your weaknesses of the car, but as soon as you put fuel in you start to feel the balance and you realise that it’s not quite there.
"So there’s a lot of work that we need to learn. Obviously qualifying is very important and crucial here, but the race is very long and a lot of things can happen."
And Perez - who was sixth ahead of Nico Rosberg in FP2 - believes a number of teams will improve in FP3 ahead of qualifying this afternoon.
"Obviously it was a good lap [in FP2], but you have the Toro Rosso’s and the Red Bulls, the Williams’ which are normally running a lot of fuel. So I expect to have a big challenge to make it into Q3."
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