After the dreadful mess up in qualifying for the Spanish Grand Prix, which cost Lewis Hamilton his brilliant pole position after they failed to put in sufficient fuel, the last thing McLaren wanted were further embarrassments during their pit stops.
But Lewis Hamilton lost time in his first one, on the 14th lap, after running over the left rear tyre that had just been removed from his car.
McLaren had already conducted an intensive investigation after the Bahrain GP into the problems that beset Hamilton twice there, and Jenson Button once in China.
"We looked at every single pit stop in slow motion," Button said. "We could see that the rear jack man can blind the guy who is waiting to change the left rear wheel."
He revealed that the mechanic who used to wield the tyre gun on the left-hand side, the source of the problems, had been changed for the last stop in Bahrain: "It's a massively tense moment. There's all the guys waiting to change your wheels and it's especially tricky for the guy on the front jack. You think, 'I really don't want to overshoot this, but I want to make it as quick as possible'. It's tricky, approaching him at 100 km/h, when there is just noise everywhere."