The 25-year-old dominated Sunday's Indian Grand Prix to extend his lead over Alonso but the two-time world champion has refused to believe that he already has one hand on a third world title.
Vettel said: "This was obviously another good step for us, but there is still a long way to go.
"It obviously feels fantastic to have a race where everything works the way you want it to, so I'm very proud, very happy and enjoying it.
"But we have seen this year how quickly things can change, so this race has gone and now we focus on Abu Dhabi this weekend. There's a lot more to come, so we'll try to take things step by step."
Vettel has moved to deny reports that he has signed a deal to race for Ferrari.