Tour de France stage 19 preview: Geraint Thomas must navigate the 'circle of death' to close in on yellow jersey

There are only three more stages between Geraint Thomas and a life-changing victory in the Tour de France. On Sunday, the procession to Paris; on Saturday, the individual time trial which should favour second-place Tom Dumoulin; and on Friday, the final mountain stage.

It is a brute, taking in three of the four climbs considered part of the Pyrénean 'circle of death': the Col d’Aspin and Col d’Aubisque sit either side of the highest pass in the French Pyrénées and one of the great Tour de France climbs, the Col du Tourmalet.

It is there that Thomas is most likely to be attacked but he will be prepared for a day of body blows from every angle. That may not come to fruition: much will depend on how much those behind him in the general classification are prepared to gamble. Is Dumoulin prepared to risk his podium place with a speculative long-range assault which might end in failure? Are those lower down in the top 10, like Romain Bardet, Nairo Quintana and Dan Martin, willing to go for a glorious and memorable stage win?

There is little for them to lose and for entertainment's sake it would be fantastic to see a showdown on the Tourmalet and Aubisque, with Thomas forced to shed his team-mates and give everything to cling on to his yellow jersey.

The problem for those chasing will not be Thomas specifically so much as Team Sky. The stage is more manageable than Wednesday's intense run to the Col du Portet, with flatter sections to control rather than only steep climbs and sheer drops. Sky are masters at dictating this kind of stage and it will take either a well-planned alliance between other teams or all-out chaos in order to shake Sky's hold on the race.

It is likely to bring a breakaway of non-GC riders who go right to the end and the winner may well come from that break, with Adam Yates and Rafal Majka likely to be in the mix. If the break is caught on the final climb then any number of riders could win it – Martin has looked particularly strong in recent days.

Chris Froome's role will be interesting to observe. Thomas said on Thursday evening that Froome would not be working for him unless he was really needed, meaning much of the burden on the key climbs will fall on the young Colombian Egan Bernal, who is having a brilliant debut Tour and was tipped by Thomas this week to be a future winner.

This is not a summit finish but a fast, technical descent from the Aubisque which would suit a rider like Julian Alaphilippe, should he still be in the mix at that point, but even the climbing specialists like Quintana could win it so long as they give themselves enough of a lead – at least 20 seconds – going over the top.

Team Sky will hope to shut it down and create a snoozefest, but there is enough packed into this stage for it to produce fireworks – if enough riders are prepared to gamble.