Froome holds a slender lead ahead of three riders tightly packed in the general classification, all within 29 seconds, with the final week ahead. Kwiatkowski, like on the stage 15 to Le Puy-en-Velay with his quick wheel change for Froome, has helped hold that lead.
"It's just great to hear from Chris, and with his thankful tweets," the Polish rider told Cycling Weekly.
"Even when we see each other, he says 'thank you' a couple of times of day."
Kwiatkowski, 2014 road world champion, developed into a stage racer for week-long races and one-day racer for races like the Ardennes Classics.
In his four years with Quick-Step, he won the Amstel Gold Race, the Volta ao Algarve and of course, the Worlds. He and the Belgian team wondered if he could switch to become a Grand Tour cyclist, but there were doubts.
The 27-year-old suffered in his first year in Team Sky after moving there at the start of 2016. He won the E3 Harelbeke, but his form took a dive through much of the rest of that season.
Kwiatkowski said in March, "There are plenty of reasons. I had health problems, but I was pushing my limits. I wanted to impress everyone in training and everywhere. I'm not like a machine, sooner or later you pay the bill.”
The difficult 2016 season made his mountain rides in this Tour de France much more impressive.
"This year I found the balance, for sure. I was back into shape each year but not for very long time, especially last year, maybe just January, February and March in 2015, then through maybe the Classics, but then it was just worse and worse.
"Also 2014, I didn't have a great Tour de France. And 2013, not a good end of season."
"I needed to find a balance between racing and training. In Team Sky last year I trained so hard, we found that being ambitious with the recon and power meters wasn't the way."
Over the winter, he sat down with head trainer Tim Kerrison and team boss David Brailsford. They decided to back off and, instead of training like Froome or Geraint Thomas, they let Kwiatkowski mix part of Sky's training in with his former methods.
The mix worked. He won the Italian one-day race Strade Bianche in March and then the big one, Monument Milan-San Remo shortly after.
And now, in the Tour de France, he is one of the most visible helpers for three-time winner Chris Froome in the mountains.
"I know that I'm in really good shape, I knew I could deliver, but for sure, I surprised myself with my climbing. I've been feeling great each day and not these gaps after such hard efforts," he added.
"It's great to win big races, but of course, it's also great to change an environment and help someone. When I signed with Sky, I was sure I wanted to be in the Tour team and support Froomey and maybe in the future, I could use it in my own results.
"If you look at G [Geraint Thomas], a great rider coming from the track and made a big step forwards, now leading the Sky team, if there'd be any sign that I could progress in the climbs and in the time trials that I'd be able to lead the team in Tirreno-Adriatico and Paris-Nice. It's just step by step."
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