Already the winner of the short, opening time trial in Malaga, over two weeks later Dennis triumphed again on the much longer course on the opposite side of the Spanish coastline.
Although Steven Kruijswijk (LottoNL-Jumbo) got off to the stronger of starts, moving ahead of Dennis by four seconds at the first checkpoint, the Australian national time trial champion made the better calculated effort, winning by more than 50 seconds over BMC Racing teammate Joey Rosskopf, with the Dutchman finally sinking to a still excellent fourth.
Two weeks ago, Dennis' time trial success in Malaga brought the additional benefit of the Vuelta leader's jersey and meant he had completed his Grand Tour 'set' of stage victories in the Giro, Tour and Vuelta.
This time around, Dennis latest result leaves him even more firmly on track for the time trial world championships, and the Australian confirmed he would be leaving the Vuelta on Tuesday evening to prepare for the Worlds team and individual time trials in Austria.
"I'm heading home now and just preparing for the time trial and team time trial at Worlds," Dennis said. "Today, I tried to control it at the start and finish and make my move in the middle section, and it worked out perfectly. I knew, obviously, I was on a good one just looking at my power on the Garmin, but really I didn't what [Michal] Kwiatkowski [Team Sky]" - the rider who ran him the closest in Malaga - "and a couple of the later guys could do."
"All I knew was what [Jonathan] Castroviejo (Movistar)" - finally third - "was doing at the time and he's a good indicator of if you're doing well or not."
Rather than himself, Dennis said that the top performance of the day had been Rosskopf riding into second, saying, "He's the best teammate, the easiest guy to be in the back of the bus with. I'm really happy for him."
Dennis said that globally in the Vuelta, "Everything had gone to plan, although I was suffering most days."
Although Tuesday marked his last day in a Grand Tour for BMC, "I've still got the team time trial and the time trial at the Worlds, one in BMC colours and I'll be on a BMC bike until December 31. Hopefully I can end it well."
He will also, he said, do the World's Road Race "to help Richie" [Porte]."
Dennis' big rival, he said, in the Worlds' time trial was clear: "Tom Dumoulin." But whatever the result in Innsbruck, for the Australian, the Vuelta a España has proved a resounding success.