Her win means that the first three stages have all been won by different cyclists, following on from Italy's Elisa Longo Borghini and her compatriot and defending champion Annemiek van Vleuten.

The CCC-Liv cyclist's win must be one of the slowest finishes of her career, leading a train of riders crawling over the line ahead of FDJ-N Aquitaine-Futuroscope's Cecilie Uttrup Ludwig of Denmark and Trek-Segafredo's Longo Borghini - two and five seconds behind respectively.

Meanwhile, overall leader and Mitchelton-Scott rider Van Vleuten held on to her pink jersey as well as the points jersey, when she finished fifth and 12 seconds adrift - close behind Germany's Liane Lippart of Team Sunweb.

Another Dutch contender, Anna van der Breggen, lost a few seconds to Van Vleuten in the general classification, but remains in second overall - one minute and 22 seconds behind.

Poland's Katarzyna Niewiadoma remains third in the standings having finished with Van der Breggen, 16 seconds behind Vos.

After the peloton entered the final kilometre together, a group of six dropped the rest on the slopes, with Vos doing enough to win her 26th Giro Rosa stage.

Although Van Vleuten was not in that six, her steady climb earned her fifth, keeping her close to the front of the pack, losing little time.

"When I saw this finish, I knew it was one for Marianne Vos," said Van Vleuten, according to CyclingNews.

"For me, it was about not losing time. 

"I was a little bit out of position [at the start of the climb], so I had to close some gaps, but I was not here for the win."

This 142.2 kilometre route spanned from Santa Fiora to Assisi, having a hilly first half before flattening out prior to the sharp climb.

Originally, the stage was to have included a third-category mountain sprint as well as an intermediate sprint in Perugia and a different finishing climb in Assisi, but the sprints were removed due to road issues, and the finish moved.

Few early breakaways were made with Poland's Malgorzata Jasinska of Cronos-Casa Dorada taking a lead that only lasted a few kilometres with around 80km still to race.

Prior to the last few minutes, the only other major break came at 38km to go and was made by Jasinska's teammate, Australian Rachel Neylan.

However, she was swallowed up by Van Vleuten and the rest of the peloton at 20km to go, despite holding a 20 second gap at one point.

In the final push, Longo Borghini was the first to attack, but Vos and Uttrup Ludwig passed the Italian before the finish.

Uttrup Ludwig remains fourth overall, 2:38 down on Van Vleuten, while Longo Borghini jumped two places to eighth, 4:16 behind and Vos rose five places to round off the top 10 with a 4:53 deficit.

Stage four will be the third of four hilly routes in a row and another opportunity to eat into the lead of Van Vleuten, who will aim to win her third title in a row.