The 24-year-old Hosking outsprinted Vos (Rabo-Liv) at the end of the 121km one day classic, named after the former world champion, with Amy Pieters (Liv-Plantur) finishing third.
“It’s so nice to put my hands up in the air, rather than watch Jolien (D’hoore), Gio (Giorgia Bronzini) or Elisa (Longo Borghini) do it,” Hosking said.
“It’s been so fantastic this year, the team’s had so many wins, and I’ve been there for a lot of them but it hasn’t been me. It’s really, really nice to be on the top step.”
The victory came after an early 11-rider break containing many of the big names of women’s cycling shook off the rest of the peloton to contest the race among themselves.
"It was really, really windy so it was always going to split up, so we had to make sure we were ready for it to happen,” Hosking said. “We knew that we had to be at the front, but we were only four so we couldn’t really afford to be the ones that started the echelon.
“When it did split we had three there, which was really fantastic, and I think we rode quite smart. We all conserved our energies, but we didn’t miss turns, so we didn’t annoy anybody.
“In the last 30km the games started to get played. Rabo was the dominant team, and we knew they wanted to win. It’s the Marianne Vos Classic, so of course they wanted to win. I spoke to the girls, and we said that we’d follow a Rabo girl each, because they had three as well.
In the end I think I timed the sprint perfectly, I jumped on Amy Pieters’s wheel with probably 300 metres to go. I thought maybe I was a little bit boxed on -Vos came on my outside - so I went back, then went forward, and I felt really, really good in the sprint."