Leonard Kemna didn't think the four climbs before the finish of the Tirreno-Adriatico stage 4 in Tortoreto were enough to beat Filippo Ganna, but by the end of the stage, the quiet Bora-Hansgrohe rider was the overall winner in Italy was wearing the blue jersey that would secure her the overall win in Italy.

Ganna made it up the 3km climb, but Kemna held on to the lead in the sprint to the finish. He finished five seconds behind stage winner Primoš Roglic (Jumbo Visma), but it was enough to lead the race.

Kemna wore the blue jersey on the podium and is now 6 seconds behind Roglic, with Joao Almedia 8 seconds back in third and UAE Team Emirates teammate Brandon McNulty 13 seconds back in fourth.

"To be honest, I underestimated this stage. I honestly underestimated the stage. I didn't think the final would be this difficult," Kemna admitted.

"But when I went through the first time, I was convinced that it was really difficult and that I even had a chance to take the jersey. I had to fight at full throttle to not lose as much time as possible."

"As a team we tried to stay in front, aggressive and aggressive, trying to cover our moves. At the end it was a full gas race.

Kemna won the third stage of the 2022 Giro d'Italia on the slopes of Mount Etna, and then spent a week in second place overall; Jai Hindley won the 2022 Corsa Rosa, giving Beulah Hansgrohe his first Grand Tour win, and he now has race experience as a leader.

"I am really, really happy to win the blue jersey. This is the first time I've won the leader's jersey in a stage race, and it's a great experience for me and the whole team at the Giro last year, so to win the leader's jersey here in Italy is very special," Kemna said.

"I definitely want to defend it. I know it will be difficult, but I want to defend it for sure. The six-second gap to Primoš Roglic is not a big one.

Kemna and Bora Hansgrohe will face hard work and hard racing in the next two days at Tirreno Adriatico.

Stage 5 ends with a 14.5 km climb to the finish in Sassottet, where snow and cold rain are likely.

Saturday's sixth stage is a short, steep and hilly stage in Le Marquet, with 20 or so steep "mulled" climbs that will gradually wear down the riders. The rider leading the race on Saturday evening will take the overall win after Sunday's flat stage to San Benedetto del Tronto.

"It's going to be a super hard two days in general, although I think the longer climbs on Friday will suit me better than the punchier climbs of today. I just have to climb as fast as I can," Kemna said.

"After the TT I was happy to be in second place behind Ganna. My main goal this year is the Giro d'Italia, to go for GC, and Tirreno-Adriatico is a big part of my preparation for that."