Frank has been plagued by illness and injury this season and has not tasted victory since the second stage of the Bayern Rundfahrt in 2014.
He had to hold off a strong chasing group that included stage 14 winner Robert Gesink (LottoNL-Jumbo), but had just enough time to celebrate what he called a 'dream come true'.
"When I crossed the line, I said to myself that this is a dream come true," Frank explained. "I have not had an amazing season. I missed out completely on my two main objectives when I had to abandon both the Tour de Suisse and the Tour de France. My ambition coming into the Vuelta was to win a stage. Now I have accomplished this mission. I feel at peace, and it's an incredible feeling."
The 2016 Vuelta will be the final Grand Tour for the IAM Cycling team after they announced their departure from the sport earlier this season. Since the announcement came, it has become one of the most successful seasons for the Swiss team with victories in all three Grand Tours. Roger Kluge kicked it off with his surprise win on stage 17 of the Giro d'Italia, and Jarlinson Pantano added one at the Tour de France.
Jonas Van Genechten completed the set with his success on stage 7 of the Vuelta, and the team has been keen to add another. Frank, who will join AG2R-La Mondiale next season, had already been in a number of breakaways, and Dries Devenyns has come close to adding a second Vuelta win for the team.
After a lengthy shakeout at the stage of stage 17, Frank and teammate Marcel Wyss made it into the 28-rider group out front. As the race approached the final 30 kilometres, Frank latched onto an attack from Dario Cataldo (Astana). With never much more than 30 seconds, it looked like it would be doomed but Frank struck out again with just two kilometres to go, keeping a chasing Leopold König (Team Sky) and Gesink at bay on the climb.
"I never imagined that the race scenario would unfold so perfectly," said Frank.
"When I attacked from the break along with Dario Cataldo 30km from the finish, quite honestly, I did not believe we'd make it. And I refused to believe until I was safe across the line. I fought hard like always. I was afraid that the chase group would catch back up. Then I realised I had won…it was magical."