Jenson Button had admitted that he is not sure what to expect regarding race strategies in Sunday's Russian Grand Prix after McLaren's promising qualifying performance.

The 2009 world champion bounced back from a poor final practice on Saturday morning to secure a fifth-place start on the grid in Sochi and the Briton has said that his change in fortunes came from a revised car set-up.

He told reporters: "With the set-up we'd adopted, the car just wasn't working for us, but, importantly, we kept our heads after that, worked through the issues, and came to qualifying with a much improved car.

"Tomorrow, I really don't know what to expect. Our long runs have been pretty good, but it isn't obvious how many pit-stops most drivers will be making.

"If you lock up here, however, you'll completely flat-spot a tyre, and, if you do that, a one-stopper will become untenable, so as I say it won't be straightforward at all."

Button finished fifth at last weekend's Japanese Grand Prix.