Last weekend’s stages in the Pyrenees will live long in the memory, first building up Sky‘s aura of invulnerability and then just as quickly exploding that myth. It was a brutal two days that taught us as much about Chris Froome‘s strength as it did about his team’s weaknesses. But here’s the kicker: it was really just a dress rehearsal for the final week’s Alpine stages, which bear more than a passing resemblance to their Pyrenean counterparts – only more brutal.

Act I: What goes up …

Let’s start with Saturday’s stage eight, which saw the familiar pattern of a Sky train riding everyone off their wheel to set up their team leader for victory. But was this really 2012 revisited?

No, it wasn’t. In 2012 Sky – aided by a parcours light on energy-sapping climbs – regularly had five or more men to drive from the base of the final climb, with Bradley Wiggins surrounded by a personal guard including Froome, Richie Porte and Michael Rogers.

On Ax 3 Domaines, however, it was just Froome plus two: Porte and, surprisingly, Tour rookie Peter Kennaugh, with Vasili Kiryienka having dropped back after working hard in pursuit of Movistar attacker Nairo Quintana. As it was, two helpers were more than enough. Kennaugh and then Porte quickly reduced the lead group to just five, setting up Froome for his stage-winning attack.

Immediately after the stage, Porte described Quintana’s long-range attack as “not a brilliant move tactically”. Actually it was a good move, as the hard pursuit blew up most of Sky’s train. Had Alejandro Valverde, Alberto Contador or others had better legs, their objective of isolating Froome might have been successful. Instead Froome demonstrated he was the strongest rider on the day, by a distance. The failure of Movistar’s ploy was physical, not tactical.

Besides, we would only see the full impact of Quintana’s attack the following day.

Act II … Must come down

As the saying goes, pride comes before a fall. Sky were brought down to earth with a thud on a day where the aggression of several teams turned a tricky stage into one which proved impossible to police.

Despite lacking a summit finish, five tough climbs on a short stage provided plentiful scope to blow up the race – although no one would have predicted quite how quickly and dramatically this would occur. By the second climb of the day, a relentless sequence of attacks initiated by Garmin-Sharp and picked up by Movistar had isolated Froome. Kennaugh lost touch after he was knocked into some bushes – after his efforts the previous day he might not have been much of a factor anyway – and, surprisingly, Porte was quickly distanced on the Col de Mente as his intense effort the previous day came home to roost.

This left the yellow jersey facing four hours of racing with no support and surrounded by his main rivals, including six men from Movistar and multiple riders from Saxo-Tinkoff, Belkin and others. However, as the race inevitably settled down it became apparent that the group was content to ride just fast enough to keep the chasing Porte at bay and wait for the final climb and descent of La Hourquette d’Ancizan.

On the ascent, Movistar sent Quintana on the attack repeatedly to test Froome’s legs. However, the race leader was equal to the challenge on each occasion and, with no attacks coming on the descent, the GC battle was effectively neutralised thereafter.

Opinion was divided after the stage as to whether Froome’s rivals, having successfully isolated the yellow jersey, had missed out on a big opportunity. But what could they have done differently? Was it a lack of courage or simple fatigue which prevented Froome’s rivals from attacking him more?

It certainly appeared that many of the 30 or so riders in the elite group were already right on the limit on the final climb. Contador, for one, is not normally one to pass up the opportunity to attack – but he had been in some distress the previous day and had clearly not recovered.

But what of others? Did Movistar have the capability to launch a one-two punch and counter-punch of Quintana and Rui Costa? Could Belkin have split their resources, sending one of Bauke Mollema and Laurens Ten Dam on the attack? What about if Dani Moreno had gone up the road on behalf of Joaquim Rodriguez? Could Valverde himself, a strong descender, have attacked over the summit in an attempt to shake off Froome on the descent? Or what if someone had attacked on the penultimate climb rather than waiting for the final one?

On paper, it’s easy to say that a more concerted approach would have at least asked more questions of Froome. The reality was that tired legs played a big part – remember, this was the ninth consecutive day of racing at the end of an increasingly hot week – as well as the knowledge that there are still two weeks to go and, while it was desirable to try to take time back from Froome, it was not necessarily imperative. Also, teams such as Belkin would have been happy to defend their unexpectedly high placings, with little incentive to attack.

And it should not be forgotten that the tactic did achieve two lesser objectives: Porte plummeted out of GC contention and Kiryienka put himself so far into the red that he missed the time cut altogether. As a result, Sky are down to eight men – effectively seven, with Geraint Thomas nursing his fractured pelvis. Their ability to control or even defend stages is severely curtailed, opening up more options for their rivals.

Would different tactics have had a different effect on the outcome of stage nine? We will never know. Or will we? Look ahead to the final week, and the opportunity to play out the same strategy rears its head once again …

Act III: What’s still to come

The importance of the Pyrenean stages becomes more apparent when you compare them side-by-side with the Alpine sequence of stages 18, 19 and 20 which will determine the outcome of the 100th Tour. Stage 18 is essentially a ramped-up version of stage eight, with the pairing of the Pailheres and Ax 3 Domaines summits substituted by two ascents of Alpe d’Huez.

Similarly, stage 19 is essentially an even more brutal version of stage nine. Two of the four cat 1s have been replaced with HC climbs placed right up front to cause immediate chaos. We will inevitably see the peloton stripped down the moment someone – I’m looking at you, Movistar and Saxo-Tinkoff – injects a bit of pace.

And finally, as if that isn’t enough already, there’s the small matter of a final summit finish on stage 20 in the equivalent space occupied by the first rest day.

So, consider the state the peloton was in after the one-two punch of the two Pyrenean stages. Now add in tougher climbs on top of an additional two weeks of fatigue. And finally tag on an extra summit finish with the potential pressure of an all-or-nothing battle for the GC. We have already established that Sky could not maintain control in the Pyrenees. Movistar’s tactics may have been only partially successful there, but it has given them some valuable data to shape their tactics in the Alps.

Now imagine them employing the same strategy (or even an improved one) on stages 18 and 19 as they did on eight and nine, perhaps with some help from a Contador who has ridden himself into form.

Sounds like fun, doesn’t it? Even if Froome makes further gains in the time trials and on Mont Ventoux, this race isn’t over yet. Far from it. What we saw last weekend, we may yet see again – potentially with a different result.