In the final 10km, Ireland's Dan Martin and Simon Yates of Britain escaped out of Aru's group to snatch back a few seconds, although both lost a place to Landa.
Thursday might have been a tough day for Chris Froome - the cyclist conceded that his legs had gone by the time he reached the final 500m ascent - but it would be foolish to write him off on the basis of a single off-day. "Simple as that. No excuses". "No excuses, I just didn't have the legs there in the final kick", he said.
"The steep finish is brutal - it ramps up to over 20 per cent, which is a really, really hard finish". The French hope overhauled Aru and won by two seconds from Colombian Rigoberto Uran, who finished in the same time as Aru.
"The race is certainly on now", he said with a smile.
He wasn't tracked down by Team Sky and went on to win the stage, but more crucially, gained 26 seconds on Froome.
White believes Froome is still the favourite to win the Tour, despite his yellow jersey loss in Thursday's 12th stage. "We have started to think, let's do what we like least when we're trying to defend", Brailsford said.
But the Briton was uninjured and his rivals spread across the road and waited to allow Froome to return to the front end of the action. The peloton trailed by 30 seconds with 30 kilometers left when Bodnar attacked to go on his own. Overall, Froome is a mere six seconds behind Aru and bookmakers remain confident that the British cyclist will triumph. For the first time in what feels like years, Froome was alone and unable to follow. It has turned into the tightest yellow jersey battle in Tour history. In addition to the stage win, he's got a comfortable lead in the KOM competition with all the points he soaked up today.More news: Oh no! Mac and cheese may contain harmful chemicals
And the Team Dimension Data rider was disappointed that his efforts ultimately fell short of a stage win as Team Sky dragged him back to the pack. This is no catastrophe on the scale of, say, 2014, when Froome crashed out of the Tour injured in the first week.
Team Sky did not regain the overall lead, but they have piled on the pressure on the other Tour contenders with a strategic long-distance attack by Froome's team-mate Mikel Landa, whilst Froome stayed behind in the group containing yellow jersey Fabio Aru.
"OK, he's not someone I would have to race straightaway if he did move, but we've seen Alberto's style of racing, he's never shy to have an attack from far out".
Aru managed to keep pace with Froome's thrusts on the final climb of the day, the category one Mur de Peguere, and the pair...
"You have to try in life", said Aru.
Quick-Step rider Martin was fifth heading into Friday's 13th stage from Saint-Girons to Foix.