Jenson Button was mystified by the McLaren team's lack of pace in the Bahrain Grand Prix, having been unable to fight the Red Bulls and Lotus cars for victory.
The Australian Grand Prix winner, who eventually was classified 18th having stopped two laps from the finish having with a differential failure, said he could not understand where the McLaren MP4-27's inherent pace had gone through the weekend.
"The pace wasn't there at the beginning," he said. "We didn't have a very good balance and we were really struggling with oversteer, so all the way through the race we were taking front end out of the car and going massively forward with the brake bias, so I think we were a long way out with the balance for the race. But the pace wasn't there anyway.
"With good pit stops we would have been much happier but still we wouldn't have been anywhere near the front guys and one to one and half seconds [of pace] is something that we don't really understand where it's gone.
"It's very difficult to understand where the pace is and why we don't have it around here. The last few races, in the race, whether we've won it or not we've had good race pace, and we don't have that here."
Button had looked in a position to secure at least fifth position until he ran into a barrage of problems in the closing stages of the race.
"The last stint was a long stint, I was interested to see what was going to happen with everyone's times," he said. "People were pushing at the beginning, I was looking after the tires and in the last five laps I was pushing pretty hard.
"I caught up with Paul di Resta and Nico Rosberg and as I got them into the DRS zone, I went into the last corner and the front tire lifted up in the air and I realized I had a puncture, so I came in.
"We changed the tires, so I went out and the car was very noisy, and the reason for the initial problem was an exhaust failure and then a puncture and then a diff failure and that's why I had to eventually retire."
Team principal Martin Whitmarsh told Sky Sports that McLaren would investigate why Button and Lewis Hamilton suffered a lack of pace, but indicated that it related to rear tire grip.
"My view is that we were just too hard on the rear tires and that really gave a great challenge to both of our drivers," he said. "Now we know that the tires have got a very small sweet spot and you have got to be operating within that, if you're outside of it then you are really giving yourself a big, big challenge.
"With the pace of the car, we've been effectively on the front row everywhere, so there is no magic. We didn't lose 50 points of downforce from yesterday to today. Clearly we are beating the tires much too hard here, we need to understand that and do a better job at the next race."