World hour record holder and European time-trial champion Victor Campenaerts (Lotto-Soudal) held the lead after starting 30th until Roglic (Jumbo-Visma), who won last weekend’s opening time-trial in Bologna, took his spot after starting 153rd.
Campenaerts placed second, while Bauke Mollema (Trek-Segafredo) had the third fastest time of the day.
“It’s perfect for today. I did a good job. Everything went good, of course I’m happy with the performance,” said the stage winner.
“We had rain from the beginning, I took it quite easy from the start and of course really carefully through the corners, and then try to go all out at the end.”
Campenaerts could have won the stage had it not been for a mechanical he suffered in the last 1.5km.
“I had a chain drop. I have to say that we didn’t practice a bike change because I’m not a GC rider, and so in general when you have a mechanical you won’t have a good result anymore.
“But when you’re at 1.5km from the finish line and you went full gas for almost 50 minutes of course, you want to still go as fast as possible to the line.”
Overall leader Valerio Conti (UAE Team Emirates) was the last man to go down the starting ramp, finishing 39th.
Roglic, who won his second stage at this year’s tour, also moved into second on the general classification, with Nans Peters (AG2R La Mondiale) completing the podium.
Riders will enjoy their first rest day tomorrow, before a 145km 10th stage between Ravenna and Modena awaits.