The breakaway soon formed. First Raúl Rota went clear, with Unai Esparza joining the youngster from Rádio Popular - Paredes - Boavista. Then Samuel Boardman joined the group.
The day was uneventful until the ascent of Senhor da Serra, which preceded the final mountain climb. About 40 km from the finish, Julen Arriola-Bengoa suffered a fall that left him badly bruised, with abrasions on various parts of his body.
The breakaway seemed to be over with 26 km to go, but Raúl Rota still attacked to go solo at the top of the climb, thus becoming the first leader of the mountain classification in this Volta a Portugal. Meanwhile, Team Vorarlberg took control of the peloton, on a day when Sabgal did the job for most of the stage.
Close to the climb, it was Emanuel Duarte who suffered a mechanical problem and the escape was neutralized for good at the base of the climb to the Vila Nova Observatory. And it was at the start of the climb that Julien Amezqueta, of Iles Balears Arabay Cycling, launched an attack, while Frederico Figueiredo pulled ahead of the group of favorites, hinting that he didn't really have any ambitions in the overall.
Little by little, the first riders from the prologue were falling behind, especially the yellow jersey, Rafael Reis. As a result, Mauricio Moreira became the virtual leader of the race. And 4.8 km from the finish, it was Jonathan Caicedo who attacked, with a direct response from Colin Stüssi, while Sabgal closed the gap at pace.
The Swiss rider then launched a counter-attack, forcing a direct response from Mauricio Moreira, who couldn't find the explosiveness, while Artem Nych and Figueiredo lost contact. Stüssi distanced himself while Jon Aguirre jumped out of the peloton to try and bridge the gap to the defending Volta a Portugal champion.
Three kilometers from the finish line, Caicedo, Delio Fernández and Henrique Casimiro lost contact, while Luís Fernandes attacked with Diego Camargo, joined by António Carvalho. Stüssi had a 30-second lead, while António Carvalho was alone with Fernandes in pursuit. Meanwhile, Mauricio Moreira broke down completely in the last 2 kilometers and António Carvalho managed to distance himself from the Credibom/ LA Alumínios / MarcosCar man. Stussi won with a considerable gap over his rivals on what may be the most important stage of the race.