Bradley Wiggins completed a British-best seventh day in the yellow jersey to maintain his overall lead at the Tour de France as Luis León Sánchez (Rabobank) won an incident-packed 14th stage that was overshadowed by tacks being thrown on the road.
Sánchez attacked with 10 kilometres remaining to shake off what remained of an escape group which had already been allowed to build up a substantial lead, crossing the line 47 seconds ahead of Peter Sagan (Liquigas-Cannondale), Sandy Casar (FDJ-Big Mat), Philippe Gilbert (BMC Racing) and Gorka Izagirre (Euskaltel-Euskadi).
But the real drama was happening in behind as a flurry of punctures decimated the yellow jersey group at the top of the final climb, 38km from home.
Worst affected was defending champion Cadel Evans (BMC Racing) who had to wait around two minutes on the narrow road for a spare rear wheel - and then suffered two more flats on the way down.
However leader Bradley Wiggins and Team Sky showed great sportsmanship as they called for the peloton to neutralise their effort to allow Evans to bridge the gap, although eighth-placed Pierre Rolland (Europcar) briefly surged clear.
Wiggins himself then had a bike change of his own and race commissaires reported that tacks in the road had caused around 30 punctures in total in the space of 4km. But thankfully the damage was limited, Rolland sitting up as the whole group came back together and rolled over the line 18 minutes and 15 seconds after Sánchez.
Jean-Francois Pescheux, competitions director of Tour organisers Amaury Sports Organisation, said: "We don't know who it was. No-one saw anything.
"We've found some of the tacks. They're the kind of tacks you use in mattresses or carpets. They were obviously thrown by a spectator.
"There were around 50 riders together in the front peloton at the top and about 30 of them ended up with punctures. Some of them had three or four nails in their tyres.
"We couldn't neutralise it straight away because we didn't know what had happened. Fortunately Team Sky neutralised the race."
It all means Wiggins still holds a two minute five seconds-lead over Team Sky colleague and compatriot Chris Froome, with Vincenzo Nibali (Liquigas-Cannondale) 2:23 adrift in third and defending champion Cadel Evans 3:19 behind.
Afterwards Wiggins said of the day's big talking point: "No one wants to see something like that have an impact on the race. As a group the thing to do was to wait, the stage win was over. The climb was over. There was nothing left to contest really.
"Everybody sees those situations differently but personally I wouldn't want to benefit from something like that. I thought the best thing to do is to wait.
"If you can't gain times on the climbs, then you don't do it when someone's punctured - not even when it's an ordinary puncture. So when it was something like what happened today, something external affecting the race, then it's even more so.
"There were so many punctures at once that it was obvious that something had happened.
"The climb was so narrow that the team cars were a long way back and waiting seemed the honourable thing to do."
That was echoed by Wiggins' Sports Director Sean Yates who said: "We saw it as a bit of an unwritten rule not to push on in that situation.
"There wasn't a great deal to be gained by it and Bradley asserted his authority a bit with the other teams to keep everything together."
The riders still have six more days of racing to negotiate, including two epic climbing tests in the Pyrenees on Wednesday and Thursday.