Geraint Thomas wins again and tightens grasp on yellow, but if you ask him, Froome is still Sky's #1 GC rider.

Geraint Thomas is wearing the yellow jersey at the Tour de France. He has won back-to-back stages in the Alps. Thursday marked the second straight day that he padded his lead over Sky teammate and defending Tour champ Chris Froome.

At least for now, however, Thomas continues to toe the party line.

“Froomey is still our leader. He knows how to race three weeks,” Thomas said after his triumph in stage 12. “Who knows? Anything can happen to me. I could lose 10 minutes.”

Thomas stayed safe through a hectic first nine stages and benefited from an excellent team time trial to put himself in great shape in the GC before the Tour arrived in the Alps. Since then, however, he has confirmed his credentials with two brilliant rides high up in the mountains. He stormed into yellow with a stage 11 victory Wednesday and rode to a second win on Thursday atop one of cycling’s best-known climbs, the Alpe d’Huez.

The Welshman survived a brutal final few kilometers on the switchbacks and then turned on the afterburners in the last few hundred meters to win the day.

“Even as I crossed the line, it was, ‘Surely there is someone still up the road,'” he said. “Insane, like not even in my wildest dreams did I think I would win at Alpe d’Huez, and to do it in the yellow jersey …”

Geraint Thomas led out the sprint and won atop Alpe d’Huez. Photo: Chris Graythen | Getty Images

Thomas now finds himself 1:39 ahead of Froome in the general classification, with third-placed Tom Dumoulin (Sunweb) a further 11 seconds back. With the Alpine stages done, Thomas will — barring a crash — likely remain in yellow through the second rest day.

Sky started this Tour de France featuring Froome as the leader, with Thomas given wildcard status after years of putting in loyal domestique work. With Froome staring down a lingering anti-doping case and coming off a hard-earned win at the Giro d’Italia, it was logical for Sky to have a second option.

Few expected that second option would enjoy a commanding race lead after the midway point of the Tour de France. And he is showing no signs of slowing down.

Froome has described Sky as being in an “amazing position” with two riders so well-placed after stage 11.

Sky principal Dave Brailsford echoed that after Thomas doubled up on stage 12.

“It doesn’t change that much, it’s still a similar position as we were in yesterday. It’s still a nice position to be in,” he said.

Thomas has publicly remained loyal to Froome in interviews. He seemed to back that up, if only briefly, on the road Thursday. When domestique Egan Bernal pulled off the front for Sky, it was Thomas who hit the front to pull back an attacking Romain Bardet (Ag2r La Mondiale). From there, he mostly followed wheels. Froome was the only one of the Sky duo to put in a sustained attack, one that was ultimately reeled in by Dumoulin.

That said, Thomas did go all in for his own stage victory aspirations in the finale, for the second day running — and for the second day running he pulled it off.

He says he’s just trying to make the best of his form for now, without knowing what the full three weeks will hold for him. After all, Thomas has never landed even a top 10 result in a grand tour. It remains to be seen whether he can keep this up into the Pyrenees.

“It would be nice [to win the Tour] but I’m tired, everyone is tired,” he said. “You don’t know what is going to happen. I am just going to try to enjoy tomorrow.”

Fred Dreier contributed to this report from L’Alpe d’Huez, France.