Come Saturday afternoon we will know which one of two riders will ride into Madrid wearing a red jersey which has changed hands as much over the last few weeks as a jazz mag in a boys dormitory (or Pippo Pozzato's hotel room, if you will).
In one corner, with a 50 second cushion, is Sicilian youngster Vincenzo Nibali, the self-proclaimed 'Shark from the Strait'; in the other is grizzled Spanish veteran Ezequiel Mosquera, known as Zeke by his nearest and dearest (apparently his favourite character in Lost is the Bearded Man from The Others, known also as Mr Friendly).
The location for the super showdown between Nibali and Mosquera is the Bola del Mundo, a brand new tortuous conclusion to the precipitous Navacerrada pass north of Madrid.
Usually the pass drops down towards the Spanish capital, but this year the route sees the riders turn onto a minor road that leads up to a cluster of telecommunications masts that stand another 300m uphill. These final three kilometres are brutal, with ramps as steep as 20 per cent. What's more, there is no tarmac surface to the road, just narrow slabs of concrete riddled with holes and divots, not so much weaving up the mountain as heading pretty much straight up at an infeasible angle.
As Garmin's Christian 'Wishbone' Vandevelde said earlier in the race: "It looks like they drove a truck up there and just dumped concrete out the back of it. It's going to be insane."
In short, it's as gruelling as a dinner with Oliver Twist - and not the kind of place you'd want, as a rider currently topping the podium, to have to defend your slender lead.
But first blood has already gone to Nibali, who suavely took a further 12 seconds from Mosquera in Toledo on Friday in what proved to be an amuse bouche of the gourmet Michelin-starred platter we're about to be served up over the weekend. If those dozen seconds prove decisive then it will be proof of Nibali's tactical acumen and clever riding.
What's more, if you believe what Nibali has said about his main rival in the past, the Shark doesn't fear the Mosquito's bite.
"I've never been scared of Mosquera," bragged Nibs after he lost a cluster of seconds to his rival in the misty, rain-swept finish to stage 15. "Look, Mosquera did five kilometres of climbing flat out and what did he gain? 11 seconds. That's no big deal for me."
If they handed out red jerseys for confidence, Nibali would have enough to dress every one of Tiger Woods' mistresses. For his part, Zeke respects the man he has trailed throughout the race.
"He has shown that he's a solid leader," said Mosquera after stage 15. "We have all attacked him and the guy held up, and didn't lose his nerve."
But one day later, atop the Cotobello, 11 seconds became 19 seconds as Mosquera clawed back a little bit more time over his rival before, quite remarkably, limiting his losses on the time trial to just 18 seconds.
With a 20-second time bonus up for grabs at the top of the Bolo del Mundo, Mosquera would move into pole position if he wins Saturday's stage with Nibs finishing more than 30 seconds behind.
But to do that, the Xacabio-Galicia rider will have to do something he has never done before in his career: win a Grand Tour stage. More likely a scenario, should Mosquera emerge victorious in this Vuelta, is that he will take 50 seconds from Nibali on the climb without taking the stage.
Either way, it looks like the man who wins the Vuelta will do so without a stage scalp - emulating Alberto Contador in this year's Tour.
So, who's it going to be? A 34-year-old journeyman who has never been on the final podium of a Grand Tour let alone won a stage, or a 25-year-old riding his first ever Vuelta who finished third in the Giro this year and who keeps on getting better and better?
Cynics will flag up Mosquera's mature age, his nationality (and the baggage that comes with it), his previous time trialling pedigree (more Rasmussian than Cancellaresque) and the fact that he's now tipped to join Riccardo Ricco at Vacansoleil, and get their I-told-you-so's primed.
The same people may raise the previous hearsay regarding Nibali: that he was tipped to join Team Sky last summer until the British team pulled out over alleged issues with his biological passport.
But where's the fun in all that? Saddles is going to sit back and appreciate the stage in the moment (well, in as much as he can - he's doing the Eurosport live coverage, after all). It should be an epic end to what has proved an unexpectedly exciting Vuelta.
BS is putting his money on Nibali holding on, though. Mosquito bites can be a right b****** but they won't exactly penetrate a shark's skin. Besides, who's heard of a mosquito that can swim under water? Although, going on that logic, who's ever heard of shark excelling out of the sea, let alone on a bike?
Nibali, however, was the rider tipped by Saddles at the beginning of the race - and he's not going to renege on that now.
The Italian may look like a Roman centurion drawn by Uderzo in the famous Asterix comics but he is mature beyond his years and in Liquigas he's got a team as solid as Lance Armstrong's defence.
As long as Roman Kreuziger delivers him to the base of the final climb to Bola del Mundo, Nibali should have the strength to hold on until the summit - even if he does lose a few seconds in the process.
And Kreuziger's departure to Astana in the close season should see Nibali - and not Giro winner Ivan Basso - emerge as indisputable top Birillo in the Liquigas team.
Come next July it may not just be about Andy Schleck and Contador over the roads of France. Nibali, on the back of becoming Vuelta champion at his first attempt, will be well and truly in the mix - while Mosquera will be just a distant memory. Besides, Vacansoleil probably won't even be invited - but that, amigos, is another story.
Follow Blazin' Saddles throughout the Vuelta and beyond on www.twitter.com/saddleblaze.