Hosking outsprinted Lotta Lepistö (Cervelo-Bigla) and the formidable Marianne Vos (Rabobank Liv) to be the first Australian woman to win on cycling's biggest stage in Paris.
Hosking is just the third winner of La Course with the previous two editions taken by Dutch riders Marianne Vos (2014) and Anna van der Breggen (2015).
"I don't think it's sunk in. I'm thinking are they coming, are they coming, and they didn't come. Just to cross the line with my hands in the air, is crazy."
Hosking enthusiastically explained her view of the finale, after appearing to jump for the line from a long way out.
"Ellen van Dijk took a flyer as we went under the tunnel. And I was jumping from train to train, Canyon were going and then Rabo came and I came through that bottom corner which is still 400 to go on Pauline's wheel and then she swung with 300 to go and I'm like "This is way too early!" and then I went, kicked, sat on Ellen's wheel and then kicked again."
After the race, the sprint star's first thoughts were with her loyal team mates.
"I still haven't seen them, they came down in some crashes, I want to know where they are.
"They were incredible. There were a few moments there where we missed that first break that had three or four in it and I looked up the peloton and I saw we were on the front. And then Amy Pieters was in a break with a lap to go and I don't even know when we caught them actually.
"Amy Roberts our young British rider was out the front, and then out the back and then out the front. She just never gave up. Our French rider Audrey was protecting me the last three laps and put me in position - so lucky!"
Hosking told Mike Tomalaris during the SBS coverage of the Tour de France she hoped it wasn't her last win this year. The Australian's eyes are fixed firmly on the World Championships in Qatar. With this win and her first ever sprint win at the recent Giro Rosa, the Canberran hits a perfectly timed purple patch of form for her October goals. She also won the second stage of the Tour of Chongming Island in May and the overall victory.
As it happened
After two laps raced, Olga Zabelinskaya (Bepink), Hannah Barnes (Canyon–SRAM), Lucinda Brand (Rabo–Liv) and favourite Chantal Blaak (Boels–Dolmans) attacked. The quartet held onto the sixth lap when Hosking's Wiggle High5 team reined them in.
A couple of crashes and the pace set by the favourites' teams dramatically reduced the peloton with 25kms to go.
Inside the final three laps Brand launched another attack down the gutter this time with Amy Pieters (Wiggle-High5) and Lauren Stephens (Team TIBCO -SVB) bridging over. Yet another crash reduced the bunch dramatically but it made the catch with three kilometres to go and the trains of the sprinters took over in the run into the finish.
Ellen van Dijk (Boels-Dolmans) then tried her luck attacking with two kilometres to race but it was to no avail as the peloton driven by Pauline Ferrand-Prévot (Rabobank Liv) closed the gap, then Hosking overtook her once she launched her sprint.
