Froome has led the race since stage 7 and has looked unshakeable since, building a lead of over three minutes on his closest challenger Quintana and maintaining it without too much fuss.
The latter, riding for Movistar, promised to take the yellow jersey from Froome in the Alps this week and he made an almighty effort yesterday, attacking the Team Sky man with five kilometres to go and pulling back 30 seconds by the finish.
It was a damage limitation exercise for Froome as not only did he lose most of his teammates early on in the comparably short 138-kilometre leg from St Jean de Maurienne to La Toussuire, but he was attacked relentlessly until he eventually began to crack.
When Froome got a stone trapped in his rear wheel with 60 kilometres left, forcing him to dismount, defending champion Niabli launched himself up the road.
The Sicilian was made to work hard to catch Europcar’s Pierre Rolland up ahead, but when he made the catch the pair worked together to build a gap over the penultimate climb, the Col du Mollard.
The Frenchman ran out of gas on La Toussuire but Nibali powered on up the 17 kilometre climb and took the win by 44 seconds from Quintana.
The latter timed his move well — though many will question if he felt so strong, why he didn’t go sooner.
The diminutive Colombian waited until Froome was a little way back in their small bunch and then sprang from that.
His teammate Alejandro Valverde did a neat little shimmy across the road, which blocked Froome’s quickest route to Quintana, meaning he had to weave towards the side of the road to get past.
Initially it looked as though Froome would bridge to Quintana, but as soon as Contador and Valverde dropped off his wheel it became clear a real gap was forming.
Froome was spat at by a fan as he tried to catch Quintana. When he crossed the line his response was predictably terse.
“I’m pretty sure he looked around, saw I was in trouble and attacked,” Froome said.
“And in my opinion you don’t do that to the race leader, it’s not sportsmanlike.” Nibali, of course, defended his honour.
“I don’t deserve the words he said, they are too hard, and not right to say,” Nibali said.
“He was very upset with me and I don’t understand his problem. But when the race is going on, there are problems, like when Alberto Contador crashed the other day.
“It was only 3km later we knew [about the mechanical]. Also, today, I didn’t hear any info on race radio. I just kept moving and going for the win.”
It’s unlikely Froome will lose the race but if he is to suffer anything like the collapse of his teammate Geraint Thomas, who dropped from 4th to 15th after losing 22 minutes, then anything is possible.
Froome will take a 2:38 lead over Quintana into today’s stage 20 showdown up Alpe d’Huez, with the Colombian’s Movistar teammate sitting in third place 5:25 down.