“Max, if you look at his performance in the second half of the (last) year, was the second highest points scorer to Lewis,” Horner told reporters.
“I don’t think he lacks anything that they have, if we can provide him the tools to do the job. I think he’s probably the driver that they fear the most.”
The 21-year-old Dutchman won two races last year, and almost won another one at Brazil, before clashing with Esteban Ocon’s Force India, handing an easy win to Lewis Hamilton, which won Mercedes the constructors’ championship, for the fifth time in a row.
Verstappen hit the headlines after Brazil, when he was ordered to do two days of public service for shoving French driver Esteban Ocon after the collision.
He did one day by accompanying the stewards at a Formula E race in Morocco last month.
“He came back and went, ‘Crikey, these guys have got difficult decisions to make. Whether you penalise or not.’ I think that was actually a useful exercise for him to see the other side of the fence,” said the Briton.
Hamilton, now 34, won 11 races for Mercedes on his way to the title while four times world champion Vettel, 31, was runner-up having won only five.
Horner said the years would eventually take their toll on Hamilton and Vettel and saw Verstappen, now the main man at the team after Australian Daniel Ricciardo left for Renault, as heir apparent.
Verstappen was the sport’s youngest driver when he made his debut with Red Bull-owned Toro Rosso as a 17-year-old and the youngest ever winner at 18 at the 2016 Spanish Grand Prix.
“I think his maturity has increased, we saw that during the course of last year. He’s just much more rounded through experience,” said Horner.
“He’s just more worldly, more experienced, he’s just in a better place to be able to deal with the pressures that are placed on him.”