Blazin' Saddles: Geraint Thomas, Chris Froome, Tom Dumoulin – who will win 2018 Tour de France?

"It's all about winning this race and as long as one of us wins – that's the main thing."

So said Welshman Geraint Thomas on the second rest day at Carcassonne – six days away from what would be a career-defining victory for both himself (a maiden Grand Tour win) or for team-mate Chris Froome (a record-equalling fifth Tour crown and a fourth Grand Tour title on the bounce).

Either scenario would clearly (re)define the careers of both riders: as the sands of time catch up, Froome may never have another chance to be uttered in the same breath as Jacques Anquetil, Eddy Merckx, Bernard Hinault and Miguel Indurain; Thomas, meanwhile, will surely never have a better chance of joining the lesser greats to have simply won a single Tour, and in doing so becoming the first Welshman to ride off with cycling's biggest prize.

There is another scenario, of course. One that involves the hitherto unity between both Sky riders coming undone and Dutchmen Tom Dumoulin capitalising to take his own first Tour win.

As it is, Team Sky have played a blinder. They're very much in control of this race. And yet it could still all come unravelling in the wake of Sunday's blow – the loss of the putative Pyrenean pace-setter Gianni Moscon, kicked off the Tour for swinging an arm at an opponent in Stage 15.

Moscon's absence means Sky, with two protected riders, will have *only* five domestiques to call on; that's still one more than fifth-place Romain Bardet and his beleaguered Ag2R-La Mondiale team. But still, it represents the first chinks in the previously impenetrable armour.

On his latest podcast for Eurosport this Sunday, the 2012 Tour winner Bradley Wiggins said that this year's Tour was "his [Thomas's] to lose". And who would argue with that?

Thomas, 32, has ridden a flawless race since the defending champion conceded 51 seconds after leaving the road 10km from the finish of the opening stage back in the Vendee. Since then Thomas has added five seconds at Mur-de-Bretagne, 20 seconds on the summit finish at La Rosiere, five seconds at Alpe d'Huez – plus the bonus seconds for winning those last two.

But the example of fellow Britain Simon Yates looms large. The 25-year-old looked destined to win the pink jersey in May's Giro until he cracked spectacularly on Stage 19 – the same day that Froome's epic solo ride saw the Kenyan-born Brit turn his race around and snare an unlikely overall win.

Yates, however, was sailing in unchartered waters. Punching very much above his weight with three stage wins and an attacking display that clearly put him in the red ahead of the decisive Queen stage.

Thomas, by contrast, is an old hand. Sure, he's never been in yellow with six stages remaining. Heck, he's never even finished about 15th place in a Grand Tour. But nor has he ever won back-to-back summit finishes in the Alps.

Records are only records until they're beaten – and if he's never been in this position before, Thomas has experienced it vicariously through his four supporting rides alongside Froome.

There remains just one more summit finish either side of two tough days in the Pyrenees, and then the all-important time trial. Still time for Thomas to collapse; still time for Sky to make a total hash of their strong position.

As Wiggins said, "The safe bet at the moment would be to put all the eggs in Geraint's basket because Froome will lose more than 10 seconds to Dumoulin in the time trial."

In other words, until Froome manages to distance Dumoulin on a climb – something he has been unable to do so far – the pendulum points towards Thomas, who has proved to be the only man capable of doing just that, besides Roglic. While not as strong as either Dumoulin or Froome against the clock, Thomas should survive that test so long as he maintains his current cushion.

It's a fascinating scenario ahead of the final phase of the race – with the intrigue between Sky's leadership poised alongside the threat posed by both Dumoulin and the rampant Roglic, who can both climb and time trial at an exceptional level. Factor in Movistar's stuttering trio of Nairo Quintana, Mikel Landa and Alejandro Valverde – who still have a lot to prove, and surely a part to play – plus the climbing forces of Bardet and Ireland's Dan Martin, and this race is far from over.

There's one theory that Thomas is riding in yellow to act as a shield for Froome, keeping Sky's top dog away from media obligations and protecting him from the potential ire of the booing fans on the side of the road.

But just look at this GIF posted by Sky over the weekend and deny that it's Thomas – serene and composed – who seems to be riding with the authority of a Tour winner-elect, and a wheezing Froome – all bend-double and out of breath – who looks very much what Sean Kelly would describe as "on the rivet".

We'd discount Froome at our peril – as the Giro so recently proved. And yet Thomas is clearly in the form of his life, having won the Dauphine and prepared for this Tour knowing that there was a big chance that he'd be Sky's Plan A regardless of whether Froome was barred from entering.

Who knows what the official hierarchy is entering the final week – perhaps even Sky don't. It may be a case of the best man wins – and if so, then no one deserves a fair crack at winning the Tour more than the man whose hard work and selflessness proved key in his current opponent's four previous wins.

Nevertheless, Thomas and Froome will have to ride tactically or risk losing out to the consistent Dumoulin. And is Froome ready to concede his crown without putting up a fight? It's doubtful.

It's another day of two races as a large break goes clear including Mitchelton-Scott duo Adam Yates and Mikel Nieve and polka dot jersey rivals Julian Alaphilippe and Warren Barguil. But it's Cofidis climber Dani Navarro who gets a second wind from the race's brief foray into his native Spain and takes an unlikely win in Bagneres-de-Luchon to end his team's decade-long wait for a Tour stage win.

Behind, it's stalemate among the GC favourites until the final climb of the Col du Portillon where Steven Kruijswijk attacks as a platform for his LottoNL-Jumbo team-mate Roglic. The top three mark each other out despite Froome and Dumoulin trading blows. Roglic and Bardet ride clear on the descent, while Froome recovers after overcooking a bend. No change on the virtual podium.

In the shortest stage of the race, Froome is distanced early on after after a mechanical as the novelty staggered-start produces a super fast ascent of the Col de Peyresourde – the same climb that he descended so well en route to victory in Bagneres-de-Luchon in 2016. When Dumoulin rides clear with the big guns, there's confusion amid the Sky camp as Thomas drops back to help pace Froome back into the fold.

The Sky duo regain contact on the Col de Val Louron-Azet just as Movistar attack through Mikel Landa and Nairo Quintana. The Colombian fades but Landa reignites his push for the top five with victory atop the Col du Portet. Behind, both Bardet and Roglic are distanced while Thomas (the moral winner of the day after his act of loyalty early on) rides clear to extend his lead. Although he fades on the final climb, Barguil does enough to take the polka dot jersey.

The Peter Sagan show gets back on track after the world champion gets into a large 30-man break to win the intermediate sprint and then pip Sonny Colbrelli for a fourth stage win at Pau. Behind, it's a ceasefire in hostilities – although an untimely puncture 20km from the finish puts Thomas under severe pressure.

It's today when the race is turned on its head after Thomas crashes on the descent of the Col d'Aspin after 85km of riding. Froome rides on with the other GC favourites but the yellow jersey is paced back into the fold on the Col du Tourmalet – although at the cost of the British team burning all its matches.

Heavy pressure from Dumoulin, Bardet, Roglic, Quintana and Landa cast Froome and Thomas out the back door and they're forced to lead chase in isolation on the Col du Soulor and the Aubisque. On the descent to the finish, Froome drops the Welshman and manages to reel in the others before taking a brave win. The bloodied Thomas battles to limit his losses, and is even cheered by the French fans for his gutsy display.

On a tough time trial course, Dumoulin and Roglic are the stand-out performers with the Slovenian taking a surprise win by just four seconds. Froome takes third place 41 seconds down with Thomas digging deep into the pain cave to cross the line 1:07 down. When the dust settles, the Dutchman leap-frogs Froome but doesn't do enough to take yellow.

Alexander Kristoff is denied by Sagan on the Champs Elysees as the Slovakian takes his fifth win of the race to secure a sixth green jersey by a record points haul of 540. Thomas wins the Tour de France by the second narrowest margin in history; Barguil wins a second consecutive polka dot jersey while Gaillaume Martin wins the white jersey.