By finishing fourth in that leading pack that sped in almost two minutes ahead of a chasing group that included the Tour's top four riders overall - Aru, Froome, French rider Romain Bardet and Colombian Rigoberto Uran - Landa clawed back valuable time in the overall standings.
Helped first by teammates Mikel Nieve and then by Mikel Landa, and booed by some spectators as he labored past them, Froome worked furiously on the climb to reel in Bardet's group. "For a guy who's doing so well in the classics and capable of winning Liege-Bastogne-Liege and Lombardy, and Fleche Wallonne, which he hasn't yet (second in 2014 and 2017) but he will some day, I'm sure, to come here to the Tour and riding for GC, very few riders can say that", added Roche. "[Team-mate Michal] Kwiatkowski gave me his wheel because the team vehicle was stuck behind". "Kwaitkowski gave me his wheel because the team vehicle was far away.We did all we could to return to the top of the race".
"AG2R had a great ride but, at some point, Chris is going to come back up, he had (team mate Mikel) Landa (helping him)". It was a time of stress.
"I didn't see any weaknesses in Froome today".
The Sunweb team rider sped into the finish in Foix, overlooked by its imposing 11th century castle decorated with a French tricolor of red, white and blue, as part of a four-man group that included Landa, two-time Tour champion Alberto Contador, and Nairo Quintana, a podium finisher at three previous Tours.
"We've always battled, we've been there and you don't lose quality overnight", said the Movistar team leader. I stayed calm and focused.
It looked like a missed opportunity for Froome's rivals as they could not capitalise on the effort he had spent making his way back over some of the steepest sections of the climb - hearing boos from the strongly pro-Bardet crowd as he went.
The main group of contenders marked each other over the rolling final kilometres, but Irishman Dan Martin was allowed to pull clear with around eight kilometres left and claw back more time.
Within 10 minutes, the 32-year-old from Team Katusha-Alpecin had opened up a one-and-a-half minute lead over the chasing pack.
The pace was set from around 60 km in by German rider Tony Martin, who made an audacious solo attack.
Diego Ulissi, Tony Gallopin and Primoz Roglic were 19 seconds slower, with the main rivals for overall victory over six minutes further back. Meanwhile, Tour de France leader Fabio Aru's task in holding onto the yellow jersey suffered a blow on Friday as key team-mate Jakob Fuglsang quit the race. That was a big goal for me.
"I've never ridden so many kilometers alone in my life", Mollema said. It was close to the chases at the end. This is the biggest win of my career so far.
As the Tour de France enters its final week, the 2,500-mile race is coming down to nerves and seconds, which makes Daniel Martin's current strategy of some interest.