Only twice in the past 60 years have a single team held the lead from start to finish through the whole of a Tour de France, but after Chris Froome took the yellow jersey from Geraint Thomas here, that remains a possibility, albeit at this stage a remote one, with the usual provisos. It is, however, quite a feat to contemplate even if in theory, as the only rider to manage it since Jacques Anquetil in 1961 was Eddy Merckx back in his pomp in 1970.

The finish here went almost totally to plan for Sky. Froome gained time on all his rivals apart from Fabio Aru, who escaped 2.4km from the top of this brutal ascent and ended the day with a net gain of 26sec on the three-time winner, time bonuses included.

Afterwards, the new race leader openly regretted that his team had given the Italian national champion so much latitude – they did not react when he made his move – and added that it would not happen again.

The Sardinian, winner of the Tour of Spain in 2015, had endured a nightmare on his debut Tour last year, cracking in the Alps when holding eighth place overall, and had been forced to miss the Giro d’Italia in May due to a knee injury. Additionally, he was hard hit, like the rest of his team, by the death of their veteran Michele Scarponi in April.

At 27, and with the support of a strong Astana team, he is ready for a serious assault on the Tour after several years playing second fiddle to Vincenzo Nibali, who left for the newly formed Bahrain Merida team last year. His attack from well back in the select lead group brought no response from Froome’s team-mates Thomas and Mikel Nieve, and he benefited further after Froome decided to test his legs with two kilometres to go.

Only three men could hang on to the Sky leader – Richie Porte, the Irishman Daniel Martin, who is often at his best on this kind of steep finish, and Romain Bardet – but Froome stalled as the road eased, letting the rest of the lead group join up again, before they all tackled the final 20% “wall” to the finish. Aru, meanwhile, was gone for good.

As the Italian sprinted for a decisive victory – and one which might bode well for his chances on the steep climbs on Sunday’s stage to Chambéry – Froome, Martin and Porte fought it out for the minor placings. At the line, behind Porte, eight riders spanned a mere 20sec, and the chances are they will vie for the top 10 in the next couple of weeks: Bardet, Simon Yates – who took the white jersey of best under-25 – Rigoberto Urán, Alberto Contador, Nairo Quintana, Thomas, Louis Meintjes and the 2016 King of the Mountains, Rafal Majka.

Aru apart, this was plain sailing for Sky, as Porte’s BMC opted to spend the entire stage pursuing an octet that looked strong enough to divide up the stage finish and the yellow jersey between them. It was hard to figure out quite why, but among the eight was the Belgian Philippe Gilbert, who can climb sufficiently well that had he taken the yellow jersey with a few minutes in hand, he might have held it for some time. In that case Sky would have been able to look to Quickstep Floors, one of the strongest squads in the race, in controlling affairs.

Better, perhaps, to keep the British squad in the driving seat on their own in the next few days.

With BMC setting the pace, Froome and his team-mates had only to sit back and wait for the climb. They emerged late in the day, and took over from the foot of the ascent, whittling down the peloton in time-honoured style. As Froome pointed out later, there was no need for a dramatic show of strength similar to the one which effectively decided the 2012 race in their favour; here it was up to their rivals to show, and only Aru was willing or able to throw down the gauntlet.

Two flat stages await before the next climbs, Saturday’s stage through the Jura to Les Rousses. Teams with no long-term interest in the yellow jersey may look to probe Team Sky’s defences to see just how keen the British team are to hang on to the lead, and how much help they receive in controlling the race from the teams of the bunch-sprinters.

Whether or not a breakaway succeeds en route to Troyes or Nuits Saint Georges, there will be trepidation as the next bunch-sprint finish approaches, after the controversy following Mark Cavendish’s crash and Peter Sagan’s expulsion in Vittel.

Cavendish said on Wednesday that he felt the race jury had made a brave decision. “It takes a lot of balls to eliminate the world champion from the Tour de France, and I commend the jury on taking a decision that wasn’t based on influences from social media or outside,” he said. “[The jury head] Philippe Marien, he’s relegated me in the past. Whether I think I’m right or wrong, the rules were there and if I break the rules I get relegated.”

On Wednesday morning Sagan made a brief statement, repeating his apology of the previous evening, and – to his credit – underlining that while he did not agree with the verdict of the referees, he was not going to argue with it. The Tour will move on for what should be a couple of routine transition stages, assuming that such days still exist in this eternally hectic race.

Tour de France 2017: Fabio Aru wins stage five, Froome takes yellow – live! Read more