Lewis Hamilton vowed to 'race his heart out' to try and come through from the back of the grid after being stripped of pole position for Sunday's Spanish Grand Prix.
The McLaren driver had taken pole by half a second, but did not have sufficient fuel in his car to get back to the pits and provide a fuel sample, as required by the regulations. He had to stop on his slowing-down lap and was later disqualified from the session, putting him to the back of the 24-car field.
"This is such a disappointment," said Hamilton. "Today's qualifying session was one of the best I've ever driven - the whole car was just rolling so smoothly - it felt fantastic.
"But, on my slowing-down lap, my engineers told me to stop on the track, and I didn't know why. Later, to hear that I'd been excluded from qualifying, was of course extremely disappointing.
"But, now, looking ahead to tomorrow, I think it's clear that it's going to be an incredibly tough race for us. Even so, as always, I'll never give up and I'll give it everything I've got. It would mean so much to me to get a good result here in Spain: it's such a pleasure to come here and the support I get is amazing.
"As I always say, and as I always do, whatever grid position I start a grand prix from, I'll always race my heart out."
Team boss Martin Whitmarsh said McLaren could take some solace from the fact that it clearly had a quick enough car to make good progress in the race.
"You won't be surprised to hear me saying that today was a very disappointing day for all at Vodafone McLaren Mercedes," he said.
"But, if I may start by stressing the positives, both today and yesterday our car has shown itself to be both fast and stable at this most testing of circuits, and as a result Jenson [Button] was extremely quick yesterday and Lewis extremely quick today."