Thibaut Pinot won Stage 14 up the legendary ascent in the Pyrenees, making amends for a disaster on Stage 10, when he lost lots of time.
Thomas cracked on the final inclines to the top of the pass and couldn't stay with Pinot and Alaphilippe, who increasingly appears to be justifying French hopes that he could become France's first Tour winner since 1985.
"Since the start of the Tour I had this stage in the back of my mind. The Tournalet, it's mythical," said Pinot, who now has three career stage wins at cycling's greatest race.
Pinot said he's fuelled by anger at all the time he squandered on Stage 10, when he was part of a group that got separated from other title contenders in cross-winds.
"I have this rage inside me, because in my opinion it was an injustice," said Pinot, a podium finisher in 2014.