Foix - Chris Froome brushed off suggestions Mikel Landa is challenging him for the leader's role at Team Sky, insisting the Spaniard is "a great card to play" at the Tour de France.
Landa caused a bit of a stir on Thursday when he kicked away from his team leader on the brutally steep finish to the 12th stage, taking fourth place, 14 seconds ahead of Froome.
And on Friday he was at it again, chasing off after Alberto Contador in the day's break and gaining almost two minutes on Froome and race leader Fabio Aru.
Landa is now up to fifth overall, just 1:9 behind Astana's Aru, who leads Froome by six seconds.
But the Briton said Landa's advances in the overall standings will work in his own favour.
"It was a great outcome for us, Mikel Landa really put in an amazing ride today and we wanted him to come back into the GC game," said the reigning champion.
"He's only a minute down now, just over a minute in fifth place - that's fantastic for us.
"It gives us cards to play, especially when Astana don't necessarily have numbers on the climbs.
"It could be a winning move for us in the days to come."
Landa had tracked an early attack from Contador and worked with his fellow Spaniard to stretch out their lead to more than two and a half minutes over Froome and Aru at one stage.
They were joined just before cresting the final climb by the counter-attackers, eventual stage winner Warren Barguil and Nairo Quintana, and stayed ahead on the 27km descent to the finish.
Landa gained 1:46 on Aru and Froome to move up the standings.
But some have suggested that Landa is now a serious threat to three-time Tour winner Froome's status as Sky's team leader.
Froome didn't say as much but acknowledged that Landa could even beat him to the title.
"We've got a lot of faith in Mikel, and I think that he showed today that he's a real threat now for the overall title in Paris," said the 32-year-old.
Aru denied he'd made a mistake in letting Landa get away, despite seeing another rival gain time on him.
"Of course Mikel was again very strong today," said the 27-year-old Italian.
"This morning he was three minutes back so when someone's further away in the standings they're given more space (to get away).
"He rode a good race."
Contador (1:52) and Quintana (1:54) both gained time too to move closer to the head of the race.
Contador is now 10th at 5:22 and still very much an outsider, but Quintana is eighth at 2:07, and Aru said he'd have to keep a closer eye on the Colombian now.
"Given he was a bit far back in standings, he had to try something," said Aru.
"I couldn't follow everyone so I concentrated on those closest to me in the standings and less so on those further back.
"Now I'll give him less leeway."
Quntana had said on Thursday his decision to ride in May's Giro d'Italia had backfired as he had "no strength" in his legs.
But he bounced back in style on Friday and now appears to be a genuine challenger again.
"We've always battled, we've been there and you don't lose quality overnight," said the Movistar team leader.
"We've always been present and leaving our mark."
Having been all doom and gloom on Thursday, Quintana's smile was back on Friday.
"Now I'm back in the GC race. We're not giving up hope and we hope to have other days like this."