With the result however Thomas did enough to cement his race lead and place one hand on the overall title ahead of the 21st and final stage which ends in Paris tomorrow. Dumoulin remained second and Froome moved back up to third in the GC, as Primož Roglič dropped to fourth.
Michael Hepburn of Mitchelton-Scott had the fastest time for a large portion of the day with his 42:14. Movistar’s Marc Soler came close to topping his time, failing by just a second.
Soren Kragh Andersen of Sunweb then surpassed it by a hefty 31 seconds (41:43). His lead was short-lived though as Michał Kwiatkowski of Team Sky almost immediately bettered his time by a second.
With the final 15 riders still out, Kwiatkowski retained his lead. Ilnur Zakarin of Katusha-Alpecin set the fastest time at the first checkpoint, but faded through the rest of the course and finished with a time of 41:54.
Chris Froome, who set off fourth last, finally bettered Kwiatkowski’s time. He created a comfortable cushion, beating the Pole’s time by almost a minute.
However, Froome’s lead was under threat as Thomas blistered through the second checkpoint 12 seconds faster. Third-placed Roglič was a bit off the pace, finishing over a minute slower than Froome.
Ultimately Dumoulin edged Froome’s time by one second, as Thomas approached the finish.
But Dumoulin’s lead stood, as Thomas put caution first to finish in 41:06.
The Team Sunweb rider was surprised to hear he had won after completing the course. “Ah that’s crazy! I didn’t know anything about the split times,” he said.
“I still thought Froome was one second ahead of me when I crossed the line; everyone was saying I was second by one second.”
He almost faced a setback this morning when his skinsuit was lost.
“This morning we found out that we lost the skinsuit, so Exteondo, our sponsor, they’re from the Basque Country on the Spanish side and they made a new one – they were sewing it this morning.
“I’m forever thankful, because otherwise I wouldn’t have been finishing in this beautiful world champion’s jersey.”