The BMC rider prevailed ahead of his fellow Italians at the end of the 176.1km stage from Pergine Valsugana to Condino.
Bradley Wiggins finished safely in a reduced peloton, 1:23 behind the stage winner, to move up to third on GC. He is 3:48 behind stage one winner Maxime Bouet and nine seconds ahead of chief rival Vincenzo Nibali going into Friday's final stage, which ends in a summit finish at Sega di Ala.
The rolling parcours offered a breakaway the chance to stay away and Team Sky's Dario Cataldo and Fabio Felline (Androni Giocattoli) went away early and opened up a five minute lead.
They were joined by Santaromita, Lampre-Merida's Scarponi and Kristijan Durasek, Tiralongo and Tanel Kangert (Astana), Cayetano Sarmiento (Cannondale), Emanuele Sella (Androni), Antonio Piedra (Caja Rural) and Stefano Locatelli (Bardiani) on the category two Fai della Paganella which peaked after 51.6km.
Cataldo was then dropped before the escape group - which held a two minute lead on the peloton - was split on the category three ascent to Daone 16km from home, with Scarponi, Tiralongo and Sarmiento going clear.
They stayed away on the downhill run to the flat finish to contest the sprint which Tiralongo led out only to be pipped by the 28-year-old from Varese who recorded his first professional victory outside team time trials.
Domenico Pozzovivo, who was fifth in Wednesday's queen stage, was involved in an early crash and the AG2R rider was forced to abandon.
The 37th edition of the four-day, five-stage 2.HC event sees most of the favourites for next month's Giro d'Italia test their legs.
- Sports & Recreation
- Bradley Wiggins
- Dario Cataldo