The Dutchman followed a great rookie campaign at Toro Rosso with a strong start to the year, which earned him a fast-track promotion to the parent outfit after four races.
Verstappen became the youngest winner in F1 history by taking victory on his Red Bull debut at the Spanish Grand Prix. The 19-year-old added another six podiums en route to fifth in the Drivers’ standings.
“He has done an enormously impressive job,” Horner said while reflecting on Verstappen’s season. “To have jumped in the car and won his first grand prix and then go on to finish on the numerous podiums that he has achieved.
“He has had stand out drives, not only Barcelona, he was very strong in Montreal, he drove brilliantly in the wet in Silverstone, he was very strong in Austria, he drove a great grand prix in Japan, very strong in Mexico.
“Brazil was an absolutely outstanding drive. And he produced another great drive in Abu Dhabi. He has marked himself out as a man of the future.”
Asked where his driver still needs to improve, Horner added: “Any sportsman can always improve in all areas. He is gaining experience all the time. As he gains that experience it just holds in better stead for the coming years. Of course there are always areas that you can improve. It is working on those marginal returns.”