The great Austrian has changed his mind.
"Sebastian can break Michael Schumacher's records," he told Servus TV, referring to Schumacher's huge tally of seven titles and 91 wins.
"He is quite clearly already in that direction, and I think he will do it," said Berger, who was Vettel's team boss at Toro Rosso when the German won his first race in 2008.
"He's not even 30 and he's already a four-time world champion," said Berger, who obviously assumes Vettel will convert his points lead into a fourth consecutive drivers' title this season.
"This (Vettel's career success so far) is really incredible," Berger added.
Indeed, even Toto Wolff - Mercedes' competition boss - thinks Vettel could continue his run of form into 2014.
Bernie Ecclestone said recently that the huge rules shake-up could produce a different winner next year, but Wolff is quoted by the Telegraph: "The performance is being driven by people, and with people staying where they are in the top teams, I don't see there will be a big swing in the balance of power."