With Mark Webber's hopes of a podium finish dashed when he stopped on lap 40 with an alternator problem, Red Bull got worried that Vettel was also going to get forced out.
Team boss Christian Horner revealed after the race that a faulty sensor from Vettel's car had indicated that there could be similar problems - which is why the team started winding down systems on the RB9 to protect its alternator.
"After the failure on Mark's car which was sudden, there was no reason to expect that it would not happen on the other car," said Horner.
"Immediately we tried to reduce the amount of draw on the alternator as much as possible – which included even turning off the KERS in the end.
"There was then a problem with the sensor on the alternator which gave us even more heart in mouth moments.
"But in the meantime, Sebastian is lighting up the timing screen with purple sectors, so there were some heart-stopping moments in there.
"But thankfully the car got to the end and Sebastian did what he needed to. It was just tremendously cruel luck not to have Mark right up there as well."
Even if Vettel had retired, though, he would still have been world champion as title rival Fernando Alonso failed to score a point.
Webber's retirement from the race once again highlighted the cruel luck that the Australian has had in his Red Bull years with reliability, but Horner was adamant there was no tangible explanation for his issues.
"If you statistically look at the time the two drivers [Webber and Vettel] have been in the car together, they have had an equal amount of issues and failures," said Horner.
"Look at the KERS issue on Seb's car in qualifying in Japan a couple of weeks ago. There is no reason to it.
"It was just tremendously bad luck for Mark today and, until Renault get the engine back, it is impossible to know what has caused it."