A large breakaway formed early in the stage, with Thomas de Gendt (Lotto-Soudal), King of the Mountains Rafal Majka (Tinkoff), Jarlinson Pantano (IAM Cycling) and Daniel Navarro (Cofidis) all clocking yet more miles up the road in the 20-strong group.

In the peloton, Astana set a furious pace on the front – Vincenzo Nibali, Diego Rosa and Paolo Tiralongo briefly getting a gap on the rest of the peloton.

With Alexey Lutsenko in the breakaway, and Andriy Grivko also getting to the front of the bunch, Fabio Aru’s team-mates were clearly following a plan to make the racing hard – a move which meant the gap to the breakaway was a small one too.

The pace-setting seemed to be causing consternation even between the Astana team-mates, with Grivko and Rosa exchanging stern words as the Italian called for the tempo to be slowed again.

The result was only a small gap to the breakaway, where De Gendt took the mountain points ahead of Majka on the Col de la Forclaz de Montmin and Col de la Forclaz de Quiege.

On the run-in to the HC Montee de Bisanne, double stage winner Tom Dumoulin (Giant-Alpecin) suffered a crash – the Dutchman abandoning the race with ‘severe wrist trauma’, which could jeopardise his Olympic time trial hopes.

White jersey Yates required a bike change, meanwhile, but was paced back to the back of the group in time for the climb.

On the ascent, Tejay van Garderen (BMC Racing) was among the riders dropped from the peloton, while the breakaway was trimmed down too with Pantano and Majka on the front.

Bauke Mollema (Trek-Segafredo) was next to lose contact at the back of the bunch, suffering a sit down on a roundabout and then nearly ending up in a ditch again on a bend just moments later.

Navarro also slid out, clutching his knee and collarbone as he was forced to follow Dumoulin in quitting the race.

Froome also suffered a crash, sliding out on a bend and taking Nibali with him – the yellow jersey torn and Froome having to take team-mate Thomas’ Pinarello Dogma F8Xlight to continue.

Costa continued to lead solo, while Bardet’s daring descending gave him a minute’s advantage over the peloton as the climbing started.

The Frenchman bridged across to Costa with 7.5km remaining, while back in the GC group Astana continued to set the pace as Froome talked frantically into the team radio near the back of the group.

Any worries the Team Sky man was suffering were allayed when Froome – on Wout Poels’ wheel – moved to the front of the chasing group though.

Bardet set the pace at the front of the race, with Costa on his wheel, as the action kicked off in the GC group with Damiano Caruso (BMC Racing) injecting some pace for Porte.

Froome followed, with Sergio Henao and Poels keeping him safe, and Nairo Quintana (Movistar) also got involved but it was Dan Martin (Etixx-QuickStep) who was next to attack.

Bardet went solo at the front, but the action in the GC group continued to heat up – Joaquim Rodriguez (Katusha) next to accelerate after Martin was brought back, while Yates struggled to hold on at the back.

Porte, Aru, Quintana and Meintjes all put in digs at the front, but the gap to Bardet continued to go up.

Aru’s spirited attack was followed by Alejandro Valverde (Movistar), whose injection of pace briefly gapped Froome at the back and forced Porte to lose contact.

Bardet was confident enough to smile and offer a thumbs up as he tackled the final section of the climb though, roared on by the partisan crowd as he got out of the saddle on the steepest section.

Rodriguez attacked to take second place from Valverde, with Quintana and Meintjes just behind to claw back a little bit of time overall.

Poels led Froome home a few moments later, earning a pat on the back and the gratitude of his race leader and Porte and Yates also rounded the final bend within a minute of Bardet.

But the day belonged to the Frenchman, who is now in line for a career-best Tour de France finish if he can hold on during the final day in the Alps.

Tour de France 2016: stage 19 – result

1) Romain Bardet (FRA) – Ag2r-La Mondiale – 4.14.08hrs
2) Joaquim Rodriguez (ESP) – Katusha +23”
3) Alejandro Valverde (ESP) – Movistar – ST
4) Louis Meintjes (RSA) – Lampre-Merida
5) Nairo Quintana (COL) – Movistar +26”
6) Fabio Aru (ITA) – Astana +28”
7) Daniel Martin (IRL) – Etixx-QuickStep – ST
8) Wout Poels (NED) – Team Sky +36”
9) Chris Froome (GBR) – Team Sky – ST
10) Richie Porte (AUS) – BMC Racing +53”

General classification

1) Chris Froome (GBR) – Team Sky – 82.10.37hrs
2) Romain Bardet (FRA) – Ag2r-La Mondiale +4.11
3) Nairo Quintana (COL) – Movistar +4.27
4) Adam Yates (GBR) – Orica-BikeExchange +4.36
5) Richie Porte (AUS) – BMC Racing +5.17
6) Fabio Aru (ITA) – Astana +6.00
7) Alejandro Valverde (ESP) – Movistar +6.20
8) Louis Meintjes (RSA) – Lampre-Merida +7.02
9) Daniel Martin (IRL) – Etixx-QuickStep +7.10
10) Bauke Mollema (NED) – Trek-Segafredo +7.42