But unlike in Pamplona, where the then-25-year-old - from the nearby town of Getxo - was the coureur regionale for Movistar, this time round, nearly 1,000 kilometres further south and on the other side of Spain, Castroviejo said there had been "no plans" for him to cross the line first and become the Vuelta's first leader again.
"It just happened like that, I wasn't expecting it, it could have been anybody" the 2011 Tour of Romandie prologue winner and former national time trial champion said afterwards. "But we'd certainly planned the time trial carefully, though.
"We made a very cautious start, and that was perhaps the key. We saw we were doing well and we got faster and faster, and more and more confident as the stage went on." The team averaged 53.177 km/h and beat Cannondale, and at that point was on track for victory against the other, bigger favorites for nearly an hour, by six seconds.
Castroviejo became a father two weeks ago and said, "I could never have expected so many good things - to become a dad and then for me to lead the Vuelta again - in such a short space of time. It's a great feeling." One of Quintana's team workers in the Giro d'Italia and presumably due to have a very similar role in the 2014 Vuelta, Castroviejo argued "this is like a reward for all that effort we put in behind the scenes. We get our moment [of success] too, before they [the race leader] have theirs."
In the case of Quintana and Valverde, and such a strong start, Castroviejo argued "it's maybe not important in the long run, but it's better for them to have those seconds advantage on [Chris] Froome (Sky) and [Alberto] Contador (Tinkoff-Saxo) than the other way round."
The first time the Vuelta started in Jerez de la Frontera, in 1979, prologue winner Joop Zoetemelk went on to take the race outright, and when it returned to the Andalusian city for another Vuelta start in 1984, winner Francesco Moser held the jersey for a week. Castroviejo is far more pessimistic about his chances: he lost the 2012 lead on stage three, and this time he said he would be lucky to stay in the top spot as long as even that.
"With so many sprinters so close behind, just a couple of seconds, maybe six, and time bonuses tomorrow, I'll be lucky if I manage to keep it. Of course we'll talk it over with the sports directors tomorrow before the stage to see if we defend the lead, but that's how I see it," he said.
Castroviejo's chances of retaining the red leader's jersey may well parallel the fortunes of Jelle Nijdam, who won stage 1 at the Vuelta (and was the race leader) in Jerez de la Frontera back in 1992. The Dutch prologue specialist was ousted from the Vuelta's top spot as soon as the second sector of stage 2.
But in any case, for Movistar and Castroviejo, taking the opening team time trial twice in three years represents the ideal start to their home Grand Tour.