The French team set a ferocious pace in the final 40 km of stage 15 into Le Puy-en-Velay, shredding the peloton, while yellow jersey incumbent Chris Froome (Team Sky) suffered an untimely puncture with 32km to go and had to fight to regain touch with the AG2R-led group.
Bardet unsuccessfully attacked on his home region’s roads and Froome didn’t lose any time to his GC rivals, apart from to Dan Martin who gained 14 seconds and now sits 1-12 behind the Briton in fifth place.
Mathias Frank, one of Bardet’s chief domestiques, told Cycling Weekly: “We split the peloton on the last climb and we were really close to getting rid of Froome and a lot of guys.
“That was actually our plan today. I think it was a great move that we did, we tried everything and we will keep trying.
“We will keep going, keep trying to crack Team Sky and try to put Romain up there to have a chance to really win this Tour.”
Frank, who finished eighth at the Tour in 2015 when riding for IAM Cycling, said that he hasn’t detected any flaws in Froome, but is optimistic that he and his team can put the Brit’s yellow jersey under threat.
“Froome is super,” Frank said. “He is a super-strong rider and he showed today that he is really in control.
Watch: Tour de France 2017 stage 15 highlights
“But, still, I think we put him in some trouble. We hurt the other guys a lot and we will keep on doing that.
“I didn’t see any weaknesses in Froome today. But, for sure, there is no moment he can relax. We always try and we have shown that in this Tour de France. We believe in creating something.
“Guys are tired and we have a super-strong team here and we have showed that today.”
After tomorrow’s rest day, the Tour moves into the Alps with two mountainous days, including the summit finish to the Col d’Izoard.
Then, on the penultimate stage, comes a 22.5km time trial in Marseille, where many predict Froome will post a time substantially better than his GC rivals.
“It will be hard [for Bardet to distance Froome] but the Alps are a different story,” Frank added.
“The climbs are much longer and all it takes in this Tour is a great day for Romain and not such a good day for Froome or all the other guys up there.
“We shouldn’t just talk about Froome; let’s not forget everybody else, there are a few guys within two minutes. It will be interesting next week.
“At the end of stage 20, your time trialling quality isn’t just on paper. How you do depends on how tired you are. But, sure, if Romain hasn’t got a decent advantage [to Froome before the time trial] it will be hard for him to keep Froome at a distance.”