The Groupama-FDJ rider came into the stage as joint-favourite alongside Wout van Aert (Jumbo-Visma) and it did look like, at least for Küng, that it was heading in that direction.
But Pogačar (UAE Team Emirates) really put out an amazing statement to decimate the field and take the stage win, but not the yellow jersey which was held onto by Mathieu van der Poel (Alpecin-Fenix).
Speaking after the stage, Küng said: "I kind of felt like if I'm going to be beaten by less than 10 seconds then maybe it could have been possible [to win], but I think everybody thinks like that when he crosses the line, although 18 seconds [is a good gap].
"I had a really good ride and did a really good performance. I was on top, I knew what I had to do. I've just been beaten by a stronger rider today. So hats off to Tadej [Pogačar]. And I'll fight back in the second TT.
There was a plethora of amazing time trial talent on the start ramp today, including Van Aert as well as Kasper Asgreen (Deceuninck - Quick-Step) and Primož Roglič (Jumbo-Visma), but the latter was holding some nasty injuries from his stage three crash.
Küng said he did see Pogačar as more of an outsider for the stage but he was focused on other riders and his own effort.
"No, honestly, I was more scared of Wout van Aert because he reminded me a little bit of Tirreno-Adriatico when I was sitting in the hot seat for a long time as well. And then he came last and he beat my time," Continued the European time trial champion.
"Tadej kind of was on my radar a little bit, but then I don't focus on other riders."
Küng did lose contact with his team car just before the second split and was riding the rest of the stage on his own really. But, Pogačar reportedly had the same issues in a similar part of the course.
"Maybe it would have been an advantage to have the intermediate time checks. But then I gave my maximum and hats off to him.
"Luckily, there's a second TT which might suit me a little bit better and I hope that he's gonna get a little bit tired during this Tour de France and then I will try to do my best."
The second time trial of the race comes right at the end on the penultimate day of the race, stage 20, Libourne to Saint-Emilion over 30.8km and another undulating course.
In the meantime, Küng will return to looking after his leaders of Arnaud Démare and David Gaudu in the sprints and mountains to come.
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