Jenson Button has admitted that McLaren needed to get everything out of their car in qualifying at the Japanese Grand Prix, but were unable to do so.
The Briton, who is widely reported to be considering his future in the sport, failed to get through Q1 and will start from 16th on the grid in Suzuka.
However, Button has revealed that there was some confusion over engine settings, which could have contributed to his performance on Saturday.
He told reporters: "The Q1 yellow flag in the middle sector meant I had to lift. Without that, I probably would have got through to Q2. However, I wasn't told in which engine mode to put the car. Every time before we start a timed lap, we're instructed over the radio to adopt a particular setting, but I didn't get told, and I went to the wrong setting.
"The car didn't feel too bad to drive – but we needed to get everything out of it today, and we didn't. You can't make a single mistake here – even going half-a-turn out on the front wing makes a big difference.
"The race will be tough for everyone tomorrow. But as usual we'll try our best."
Button's teammate Fernando Alonso will start in 14th place.