This was no gentle run to the foothills of the Alps. As Daniel Martin observed, the Tour de France can be lost on any given day and this apparently innocuous 100 miles dealt a potentially fatal blow to the Irishman’s ambition to finish on the podium. After a stage dominated by the Sunweb team, who took their third victory in five days with Michael Matthews, Martin lost 51sec to the other favourites when the race split in strong crosswinds with 12km to go; he slipped from fifth to seventh overall.

This was a dire day for Martin’s Quick-Step team. In the morning the Belgian squad lost the former world champion Philippe Gilbert to gastroenteritis. In the afternoon their points leader, Marcel Kittel, dropped a host of points to Matthews, winner of both the intermediate sprint and the stage itself, enabling the Australian to gain a maximum 50 points on the day, closing to 29 points behind Kittel.

Martin and the South African Louis Meintjes were the main victims of a high-speed stage dominated initially by a battle between Quick-Step and Sunweb, with the finale buffeted by a strong south-westerly. The source of Martin’s travails could be traced back into the highlands, where Kittel slipped off the back of the peloton as it climbed out of Le Puy-en-Velay, with Matthews “attacking like a maniac”, as he said later.

With Kittel gone, “the [Sunweb] boys came to the front with big smiles on their faces and rode flat out,” said Matthews. Their objective was to open a decisive gap on the green jersey and a 50-strong group that had formed around him, thus setting up Matthews’s assault on the points award. With the help of Steve Cummings – who had his eye on a stage win for Edvald Boasson Hagen – they did not relax for over 100km, until after the intermediate sprint on the other side of the Rhône.

Tour de France 2017: Michael Matthews wins stage 16 in photo finish – live! Read more

By then the tension could be felt in the peloton as the wind bent trees in the Rhône valley and the splits began emerging in the final 15km as first Trek-Segafredo and then Team Sky began to force the pace. Within seconds the 120-strong front group was in pieces, as a lead pack of 28 formed, containing all the top 10 overall apart from Martin and Meintjes. Nairo Quintana was in the mix, Alberto Contador further back.

At this critical moment Martin had only two team-mates with him; the four other Quick-Step riders had remained with Kittel, partly because two of them were under the weather. Only Jack Bauer put in any sustained effort, along with Meintjes and his two UAE team-mates: their firepower was nowhere near enough, as all the 28-strong leading group – even Chris Froome, Fabio Aru and Quintana – were contributing to the pacemaking up ahead.

In the space of three or four kilometres Martin’s 13-strong group lost 30sec and once the race had turned left to take the howling wind on their backs, that was that.

With the lead group travelling at 65kph, the Irishman’s little peloton would have needed to be going at an unfeasible speed to regain contact. He and Bauer received little help – and a certain amount of hindrance from members of AG2R and Orica – and eventually the New Zealander ran out of gas.

Matthews’s second stage win of the Tour came at the expense of Boasson Hagen, who is finding new and ever more frustrating ways to finish runner-up. Here he was poorly placed at the top of the little climb from the Isère in the final kilometre but made up ground in the last 200 metres as Matthews launched his sprint in the wake of Greg Van Avermaet. The Norwegian closed to just under a wheel, while, on Matthews’s right – no sprint here is possible without even a soupçon of controversy – John Degenkolb was waving his arm in annoyance; he had a brief altercation with Matthews after the finish but his protest went nowhere.

Abruptly the Alps loom large. The Cols de la Croix de Fer and du Galibier entail 24km and 28km of climbing respectively – if the Col du Télégraphe “prequel” to the Galibier is included – making them of a scale not seen so far in this race. If the margins remain tight, that is partly because the climbs have been brief and steep. Here the gaps could be counted in minutes.

To jolt the nerves even more, Matthews and Sunweb are bound to target the early intermediate sprint, coming as it does after a second-category ascent where Kittel can be dislodged. It will be a fast start and for many a grim finish.