"Let's see if it will be lucky in seven days time in Sao Paulo," said Ferrari in a post-race statement.
Actually, the points gap gives Vettel a huge advantage for the 2012 finale, because even if Alonso can drag his less competitive car to the top of the Interlagos podium, Red Bull's German could then finish just fourth and still be champion.
"Maybe on paper that chance is not so big, maybe 25 per cent," Spaniard Alonso, who has been quoting much bigger percentage chances recently, said after Austin.
"But deep down, I feel it (the chance) is much more than that.
"Anything can happen at Interlagos and we saw again how important reliability can be, didn't we?"
He is referring to Mark Webber's failure in the sister Red Bull on Sunday with yet another alternator problem.
And there is also a forecast of rain for Sunday in Brazil.
"Clearly, if it's dry and we have a normal race, one can expect Red Bull to be in front of everyone and us on the third or fourth row, so the more unknown factors there are, the better it is for us," said Alonso.
Jaime Alguersuari, a former Red Bull-contracted driver but a Spaniard like Alonso, thinks Vettel will be heading to Sao Paulo feeling nervous.
Asked if the title is now all but decided, he told Mundo Deportivo: "For the best car yes, for the best driver, no.
"Brazil will be a very uncomfortable race for Vettel, and very comfortable for Fernando," he said.
"Vettel can only lose the championship, because in theory he has already won. But theory doesn't give you ten points.
"Fernando, who at the age of 31 knows something about Formula One after 11 years, is already the de-facto runner-up and so he can only win.
"Who has been involved in elite sport knows what can go wrong when you are defending an advantage, and how well you can go when you have nothing to lose.
"So Brazil will give us something very interesting," said Alguersuari.