Alonso would have to win three of the remaining races and finish second in the other, with the Red Bull driver retiring from them all to deny Vettel the accolade.
"I am not really thinking about that," Vettel told reporters. "It is the big target we set when we started the season once we realised we had a strong package.
"It is very strange because the season is very long still and we have the chance to wrap it up. But I am not thinking about it.
"I am looking forward to getting home and relaxing a bit before we go out to India, a circuit I like, a country that is really impressive, and not thinking about where we have to finish to win the championship."
The win was Vettel's fifth in a row.