Team Sky's Wout Poels lifted his pace a notch to respond to the Frenchman, and the invisible ties that tethered van Garderen to the rear of the group of favourites were broken. Cut adrift, the American was left to beat against the current, and he was already almost a minute down by the time he crested the summit.
After navigating a perilous descent, van Garderen reached the finish in Culoz 1:28 behind yellow jersey Chris Froome (Team Sky) and the rest of the podium contenders. He drops two places to 8th overall, now 4:47 down on Froome and more than two minutes off a podium berth in Paris.
"I wasn't really thinking anything, I was just really in my own world, trying to hold the wheel in front of me but I just couldn't hold it," a downcast van Garderen said as he warmed down outside the BMC bus after the stage.
Van Garderen was already betraying some signs of suffering on the penultimate ascent, the Grand Colombier, where Astana's Diego Rosa stretched out the group of favourites with a prodigious bout of pace-making. The descent offered some respite, but once the road began to climb again on the day's final haul over the Lacets du Grand Colombier, it was clear that he was only treading water.
"To be honest, I felt fine, it was just the pace was really incredible," van Garderen said. "I can't say that it was bad sensations, it was just above the level I had on the day."
Van Garderen shrugged off a request to assess his current position on general classification – "I haven't even seen the results," he said quietly – but for the first time on this Tour, the American now sits behind his teammate Richie Porte in the overall standings.
Get The Leadout Newsletter
The latest race content, interviews, features, reviews and expert buying guides, direct to your inbox!
Porte finished safely in the Froome group on the stage to move up to 7th place, 20 seconds ahead of van Garderen, though BMC's dual-pronged approach to the question of team leadership remains resolutely in place.
While van Garderen was distanced on the final ascent, Porte was of the opinion that the damage had been done by Rosa's fierce tempo on the upper slopes of the preceding Grand Colombier. Few riders had the strength to even contemplate attacking the maillot jaune in the finale, and, not for the first time on this Tour, the selection came from the back.
"It wasn't so bad the last time up [the Grand Colombier] but the second last time, everybody was on the limit, especially when Diego Rosa was on the front. His effort put a few guys' days to an end," Porte said. "I'm happy to come through it."
Monday's leg to Bern ought not to trouble the general classification contenders, but a fearsome finale in the Alps awaits when the race resumes after Tuesday's rest day. In the lead-up to this Tour, van Garderen placed great store on his ability to recover better than most in the third week of racing. He will have to hope that aptitude has not deserted him.
"Anything can happen," van Garderen said when asked if Sky were invulnerable. "Once you get into the last week of a Grand Tour it could be like Russian Roulette. It's anyone's day."
Barry Ryan is Head of Features at Cyclingnews. He has covered professional cycling since 2010, reporting from the Tour de France, Giro d’Italia and events from Argentina to Japan. His writing has appeared in The Independent, Procycling and Cycling Plus. He is the author of The Ascent: Sean Kelly, Stephen Roche and the Rise of Irish Cycling’s Golden Generation, published by Gill Books.
