The German led every lap of the grand prix en route to his seventh successive race triumph, which drew him level with Michael Schumacher's tally of consecutive wins in a single season.
Horner stopped short of labelling his driver the best of all time, but did seem to have run out of superlatives for the 26-year-old.
"I think Sebastian has stepped it up another gear," he said.
"Times are very different. We are all on a standard tyre now, there is no testing and we are limited on how many engines we can have, so it is a much more even playing field (than in the past)].
"It is always difficult to compare generations to generations but, at the level he is performing, I don't have words to describe how phenomenal he is."
Vettel's team-mate Mark Webber had threatened to end the German's streak of wins when he sealed pole position on Saturday.
But the champion was unperturbed, storming into the lead at the first corner and refusing to relinquish it for the next 55 laps.
Webber took second place, with the Mercedes of Nico Rosberg taking the final podium position, but Vettel's class saw him finish over 30 seconds clear of his team-mate, leaving Horner full of praise for the drive.
"It was truly impressive, absolutely mind-blowing in many respects," he said.
"After the start, Seb just got his head down and disappeared. He had the longevity and at no point did he look under any threat.
"He won by a very dominant margin that could have been even greater in the end if he hadn't managed the pace after the second pit stop. It is truly dominant. He has just hit a patch of form which is incredible.
"We know Mark Webber is a very fine racing driver and, in a race which didn't have any safety cars or issues, to achieve what he has done is quite mind-blowing. It is really impressive to witness."