The AG2R La Mondiale rider moved away from a breakaway group and held off the chasers in the final climb, triumphing in a time of 4 hours 41min 34sec on the 181 kilometres route from Commezzadura to Anterselva/Antholz.

Colombia’s Esteban Chaves of Mitchelton-Scott finished 94 seconds behind in second place.

Italy’s Davide Formolo of Bora–Hansgrohe was a further 17 seconds back in third.

"It’s enormous," said 25-year-old Peters, the young rider classification leader after stages nine, 10 and 11.

"My Giro was already a success with the white jersey at half way. 

"It’s incredible to get my first pro win in a Grand Tour. 

"In the breakaway, I promised myself to attack only once and the timing proved to be right."

Ecuador's Richard Carapaz of Movistar Team kept hold of the general classification lead as he celebrated his 26th birthday.

His overall time now stands at 74:48:18.

Nearest challenger, Italy’s Vincenzo Nibali of Bahrain-Merida, is 1min 54sec back.

Third-place is occupied by Slovenia’s Primož Roglič of Team Jumbo-Visma, 2:16 behind.

Carapaz’s team-mate Mikel Landa of Spain sits in fourth spot.

"Mikel Landa felt good in the finale and decided to attack to gain some time for the final podium," Carapaz said.

"I also felt good and I did my best to profit from Mikel’s attack. 

"I couldn’t have asked for a better 26th birthday than with the Maglia Rosa."

The 21-stage race is due to continue tomorrow with a 222km route from Valdaora/Olang to Santa Maria Di Sala. 

Action is scheduled to conclude with a time trial in Verona on Sunday (June 2).