Both teams started cautiously in a dull first half, where each side registered a single shot on target.
Fiorentina continued to comfortably hold on to the ball after the break but Cremonese's defence successfully thwarted their few goal-scoring chances.
The visitors regained some of the possession towards the end of the game but lacked the quality to overturn the deficit.
Fiorentina will meet Inter in the final on May 24 at the Stadio Olimpico, after Simone Inzaghi's side beat Juventus 1-0 on Wednesday to secure a 2-1 aggregate victory.
- Livio Marinelli