McLaren team chief Martin Whitmarsh admitted Sunday the team error that resulted in Lewis Hamilton losing pole position for the Spanish Grand Prix could also cost the Briton a second drivers' title.
Hamilton clocked the fastest time in qualifying Saturday to claim pole position, only to be relegared to the back of the field because he did not return to the pits with his McLaren car after setting his fastest lap.
Instead, he followed urgent orders transmitted by the team and stopped out on the track. He required assistance to return to the pits where a one litre fuel sample was to be taken.
Whitmarsh said the mistake, made in analysis of the fuel load needed by Hamilton for his final flying run in qualifying, had caused a lot of pain to the team and the team members responsible for the error.
"There was an error in the refuelling process and we know that by the analysis," he told the BBC. "We know just one of those errors could cost us the title.
"There is lots of pain in people's hearts about this in the team, from me all the way down. I had lots of conversations with Lewis (Hamilton) last night and he was inevitably shocked by this.
"And he was disappointed as you would expect from as competitive a person as him.
"But by the end of the evening, he was extraordinary. He was talking as a team member, saying he was going to come out and give us the best from the back of the grid."
The error means Venezuelan Pastor Maldonado of Williams will start from pole for the first time after being promoted from second on the grid.
Williams have their first pole since Nico Hulkenberg secured his maiden and sole pole position at the 2010 Brazilian Grand Prix.
It is also the first ever for a Venezuelan driver.