Ever cautious, calm and understated after his stage win, Nibali noted that three big Alpine climbs still await Saturday and other punishing ascents are on tap in the Pyrenees next week.
"For the coming days, I only know that I have to remain quiet," he said.
But in the winner's circle, where he collected the yellow jersey for the 11th time this year, Nibali perhaps let slip a bit more happy emotion knowing that a first Tour victory for an Italian since Marco Pantani in 1998 just got a little closer.
"I expect more attacks tomorrow in another very hard stage and next week," Nibali said. "My advantage over Porte is good now. He's the rider I feared the most in the closing time trial."
If Nibali's mountain dominance keeps up on Monday, he won the only other high-mountain stage so far the 54-kilometer (33-mile) time-trial in Stage 20 from Bergerac to Perigueux is the only real challenge left in his way.
The unexpected has gone Nibali's way. He surprised himself by winning an up-and-down Stage 2 stage in the hills and dales of Yorkshire and capturing his first Tour yellow jersey. He mastered cobblestone treachery in Stage 5, when 2012 Tour champ Chris Froome crashed out. And then, two-time Tour winner Alberto Contador went out five stages later after a fast downhill crash fractured his tibia.
Stage 14 preview
Saturday, 5 a.m. TV • NBCSN (re-aired at noon on Ch. 5)
About the stage • The final day in the Alps will be 110 miles from Grenoble to Risoul. Riders will tackle legendary Alpine summits Lauteret and Izoard before the summit finish at Risoul, an 8-mile climb at an average slope of 6.9 percent.
Leaders • 1. Vincenzo Nibali, Italy, 56 hours, 44 minutes, 3 seconds. 2. Alejandro Valverde, Spain, 3:37 seconds behind. 3. Romain Bardet, France, 4:24. Also • 5. Tejay van Garderen, United States, 5:19.