Horner: we're not Ferrari's guinea pigs

Horner has revealed in Malaysia that Coulthard's problem was identical to that of Ferrari driver Felipe Massa. Both have new V8s for the Malaysian race and face 10-place grid penalties this weekend, because the failures occurred after the chequered flag in Bahrain.

"Our agreement with Ferrari is straight forward," said Horner. "We have the same engines, but one cycle of development behind. But we shouldn't be used as a guinea pig. It wouldn't be in Ferrari's interest to do that.

"It's hugely unlucky to have a failure on your slowing down lap, especially when you're running just outside the points," he added.

"For Massa and David to be running in ninth and 10th positions - it's the worst possible place to have an engine failure, as we didn't get a point out of it at least."

Horner explained that Red Bull did manage to stop Coulthard before the engine actually blew up.

"We could see the straight-line speed had disappeared quite dramatically, and it was difficult to pass [Nico] Rosberg," he said.

"I think the failure was coming from three laps earlier. But the first time we were informed of the failure [by Ferrari] was after the chequered flag. Which is a little bit too late."

Coulthard questioned whether there is a case for reviewing the grid penalty rules.

"There was clearly a drop-off in performance from the engine in the last few laps," he said, "and it would have been nice to have known that and stopped the car before the chequered flag, which meant that I wouldn't have got the penalty here.

"But because I crossed the line, 10th place, no points, and I get a penalty. I know those are the same rules for everyone, but it just seems a bit strange that it can't be reviewed."