Jenson Button has suggested that McLaren's pace was the defining factor to see him through the first part of qualifying at the Russian Grand Prix.
The Briton, who will continue racing for the Woking-based outfit in 2016, finished ahead of teammate Fernando Alonso and will start from 13th on the grid at the Sochi circuit.
However, Button has predicted that McLaren will struggle in Sunday's race at the Black Sea resort.
He told BBC Sport: "We got through to Q2 because of the actual speed rather than issues other people had. The last run I couldn't find any grip.
"We planned the weekend well so far well but tomorrow will be very difficult for us. It is one of the more difficult circuits for us because of deployment and fuel. We will do our best. This is really testing for us."
McLaren are currently ninth in the constructors' standings.
