While Froome looked to cement his ever expanding overall cushion of time, he wasn't happy to just finish second again to early pace setter Dumoulin in a time trial at this year's Tour.
The Team Sky rider paced his time trial well, setting up a strong push in the back half of the course after a conservative initial time check to fly home in a time of 30 minutes and 43 seconds.
"I really didn't expect to beat Tom today. I'm happy with that," Froome said.
"I have a great advantage with two days to go. I keep the yellow jersey on my shoulders, but the next two days are really tough.
"The main thing for me is to stay out of trouble. I will not try to win a stage uphill.”
The two time Tour de France winner said his victory today came down to choosing the right equipment on the hilly route.
"When I saw the course, I thought I'd ride with the road bike but after the team analyzed it, we opted for a full TT set up. The other aspect was pacing. For all those who started too fast, it was easy to get carried away. I didn't," he said.
Dutchman Dumoulin felt like he didn't give his all.
"I think I didn't ride my very best time trial. Froome showed he was simply the best. In the very steep part in the beginning I felt good and performing well and then I lost lots of energy in the intermediate section.
"I spent a long time in the hot seat but I expected it would be very hard. I knew it would be close.”
Fabio Aru (Astana) rounded out the podium for the stage, posting a time of 31 minutes and 37 seconds. The Vuelta champion hasn't had the best of Tours, but overtook Alejandro Valverde (Movistar) to leapfrog into seventh overall.
Richie Porte (BMC Racing) finished in the same time as Aru, putting his unimpressive stage 13 time trial behind him. The Tasmanian remains in sixth place overall but is just 44 seconds behind Adam Yates (Orica-BikeExchange) who currently stands on the third podium step.
“I had a very good time trial. I couldn't have gone faster. I'm really looking forward to taking my chance and fighting for that podium," Porte said.
"What I did today shows that I'm climbing really well at the moment. The team is fully behind me. The podium is so tight. I'll have to see where to take some time back.”
The Tasmanian has a fight on his hands to make the podium with the top six overall behind Froome tightly crammed. Just one minute and eight seconds separates Bauke Mollema (Trek-Segafredo), Adam Yates (Orica-BikeExchange), Nairo Quintana (Movistar), Romain Bardet (AG2R) and Porte.
Yates (3rd overall) and Mollema (2nd overall) rode middling time trials and finished 16th and 17th respectively, their overall advantage slipping to those chasing behind.
Quintana looked to struggle at some points on course, but he finished 10th on the stage and slashed Yates' lead over him to just 21 seconds. Fourth overall, the Colombian could still yet redeem his Tour on the remaining stages to podium in Paris.
Only one spot further down on the overall, Romain Bardet also impressed in the race against the clock. The Frenchman finished fifth on the stage and now leads Porte by just three seconds with two stages left in the mountains.