Christian Horner has revealed that McLaren's superior pace in qualifying forced Red Bull's hand when it came to Sebastian Vettel's tyre choice.
With McLaren looking set to romp away with pole position at the Sepang circuit on Saturday, Red Bull made the very unusual choice of putting Vettel on the harder Pirelli compound.
The decision meant that while McLaren claimed the 1-2, Vettel was down in sixth place 0.415s off the pace. Mark Webber, who qualified on the softer tyres like the McLaren drivers, is fourth on the grid.
"It was quite a late call at the end of the day," Horner told Sky Sports F1.
"We didn't feel we quite had the pace today to take the McLarens on over a lap, so that's why we decided to split the strategies with the two drivers.
"Sebastian had an extra set of primes available to him having not used two sets in Q1, so we felt to split the strategies probably wasn't a bad thing all considered."
Pressed to what kind of advantage starting on the harder more durable tyres will give Vettel, Horner said: "I've got no idea.
"Theoretically the prime should run a bit longer and be a bit more consistent. But we'll see tomorrow.
"If we had just run the soft tyre we'd have qualified probably absolute optimum third and fourth, we've qualified fourth, and with Raikkonen's penalty, fifth. And we've split the strategies.
"We've got both options or both strategies covered and hopefully we can give the McLarens a good race tomorrow. They are very, very quick here as they've showed all weekend but hopefully our race pace will be good tomorrow."
As for Vettel, the reigning World Champ says he supported the tyre call as his RB8 was handling better on the harder compound.
"We didn't feel so good on the medium compound tyre, so we decided to go onto the harder tyre for the final lap, which was a step forward," said the German.
"I didn't feel that good in the car and was struggling to find the balance, so I didn't get everything out of it for one flying lap.
"There's not been much time to react since Australia - only one week. The McLarens were strong in Australia and they are strong here, so they are the ones to beat.
"I think in race trim we might look a bit better, but nonetheless I think you can see that we don't have the easiest car to drive, we are aware of that and are pushing very hard."