Vettel, who stands on the brink of a fourth world title, was fastest in Friday morning's opening practice session and improved further in the afternoon, lowering the benchmark to one minute 25.722 seconds to finish three tenths of a second clear of the chasing pack.
Despite the rest of the field once again being left in his wake, the Red Bull driver insists he is yet to show his true pace around the fast sweeps of the Buddh International Circuit.
"The soft tyre is not lasting so long here, but it's Friday and the track is still rubbering in," the German said after leading a Red Bull one-two in both practice sessions.
"It's normally improving for Saturday, plus we haven't used this tyre compound for a long time, so tomorrow it should be better."
Vettel will enter the qualifying hour as the red-hot favourite to take pole position and with it continue his dominance at a race he has always won since it came onto the calendar in 2011.
Regardless of whether Vettel wins in India yet again, the primary objective this weekend is to wrap up world title number four, which would put him in an elite group comprising Juan Manuel Fangio, Alain Prost and Michael Schumacher.
With four rounds left, Vettel enjoys a 90-point lead over Ferrari's Fernando Alonso and needs to finish no lower than fifth on Sunday to be sure of retaining his title.
With much of the focus ahead on Vettel's title bid, it has been easy to overlook the fact that his Red Bull team are also on the brink of their fourth championship win in as many years.
Red Bull team principal Christian Horner says achieving a "quadruple double" would be a stunning achievement but is steadfastly refusing to take anything for granted.
Red Bull are 148 points clear of Ferrari in the race for the constructors' crown and after Vettel's recent run of five straight wins dating back the summer's Belgian Grand Prix, the general consensus is that it is only a matter of time before the team can start popping champagne corks.
Horner, however, is holding off until every last shred of doubt has been removed.
"Should we achieve a quadruple double championship it would be an amazing feat for every single member of the team to achieve such results against such illustrious opposition, but those thoughts aren't really on our mind at the moment - our focus is very much on this event," Horner said.
"The championship tables obviously look very healthy but it's never done until it's mathematically impossible for anybody else to win.
"The whole team's focus is very much on getting the most out of this weekend and the championships take care of themselves."