The Pole, who wore the white jersey earlier in the race, has looked to limit his loses in the Alps but came unstuck on the brutally tough stage to Le Grand Bornand, losing ground to his GC rivals and dropping from ninth to tenth.
"For the whole day I had the support from my teammates and I thank them, especially Peter Velits who stayed with me until the end and he did an amazing job," he said at the finish.
Kwiatkowski lost contact with the leaders on the final climb of the Col de la Croix Fry, as Saxo-Tinkoff looked to defend Alberto Contador's second place overall and set a furious pace on the front.
"We just took our own pace because for me it's better not to go over my limit because after that it could have been difficult to finish the stage and I could really for it tomorrow," said Kwiatkowski. "We lost some time to the best riders but tomorrow is the last hard day."
Laurens ten Dam (Belkin) finished in the same time as Kwiatkowski, 10:10 down on stage winner Rui Costa (Movistar), and currently sits in 11th but the danger man to Kwiatkowski's top ten hopes could be the American, Andrew Talansky (Garmin-Sharp), who hung onto Saxo-Tinkoff's coattails and put a minute and thirty seconds into Kwiatkowski by the finish. The pair are now separated by 16 seconds.
"It's possible that I can keep tenth but I've heard that Saturday's stage is pretty hard. I don't know what the difference is between me and the riders behind me but I'll do everything to defend 10th position in GC," he told Cyclingnews.
Whether Kwiatkowski slips down the Tour standings or not this has been a successful race for the 23-year-old. He finished 136th in his debut three week race at the Giro last year but in 2013 he has been consistently present at the head of major races. He briefly led the Tour de San Luis back in January before finishing second at the Volta ao Algarve. That result was backed up by fourth in Tirreno-Adriatico, fourth in Amstel Gold, fifth in Fleche Wallonne, and a win in the Polish national championships.
"The whole team can be happy with our Tour," he said. "I had the white jersey for a few days and we've won four stages already, so that's a good Tour for us."
Asked if would return to the Tour de France with greater ambitions, even of winning the race, he replied, saying, "It's too early to say. I'm still 23 years old. I think we have to discuss that with the team, the directors and the coaches about my future but we will see."