Bilbao really made a name for himself when he finished sixth last year at the Giro, but put his name in the record books as a stage winner with his win up the punchy climb to the stage finish in L'Aquila.
"It was a really important day for me today," said Bilbao. "It took a long time to get my first victory in a three-week race. This was only possible with a big team like Astana. Thank you to all of the team."
The eventual winning move took a long time to go, with a number of skirmishes off the front of the race shut down in the opening kilometres after being determined to be too dangerous.
After 40 kilometres of racing a group consisting of Bilbao, Cattaneo Antonio Pedrero (Movistar), Andrey Zeits (Astana), Gallopin, Formolo, Jay McCarthy (Bora-Hansgrohe), Ruben Plaza (Israel Cycling Academy), Thomas De Gendt (Lotto Soudal), Lucas Hamilton (Mitchelton-Scott), JJ Rojas (Movistar) and Sebastian Henao (Team Ineos) went clear.
Rojas was a danger to race leader Valerio Conti's pink jersey, going into the stage just two minutes and 12 seconds behind the UAE Team Emirates rider, so the break was given little leeway throughout the stage.
"Today was really complicated to go in the break," said Bilbao. "In the end I also started to go in the big groups because we saw dangerous groups were going. I tried, I had legs, and until the end.
"It was a really big advantage (to have Zeits in the breakaway) because Andrey was pulling really hard. That's why we kept a gap to be more relaxed and to only think of the victory. He did impressive."
Australian Lucas Hamilton wasn't best suited to the punchy finish, but attempted a late attack and ended up finishing fourth on the stage.
“After yesterday with the jersey swapping hands, we knew today was going to be another good day for the break so the team did a really good job and managed to put the other teams under pressure by being in every move and obviously the one I ended up in went to the line.
“It’s always a risk, but there’s days better suited towards a breakaway than others. Today definitely suited it and that was obvious with the breakaway taking over 80km to go.
“The climb didn’t really suit me in the finish, I prefer them a bit longer, it was a bit too punchy for me, but I thought I would try early to try to get away and maybe the group would stop working, but Formolo kept everyone together until Bilbao launched.”
Conti kept his race lead thatnks to the work of his team, with Rojas moving up the second in the battle for pink, a minute and 32 seconds behind the Italian.