Holders Juventus crashed out of the Coppa Italia on Wednesday with a 3-0 defeat at Atalanta, as striker Duvan Zapata scored twice to continue with his electric form.
Castagne caught out Joao Cancelo and drilled home from the edge of the box to put the hosts ahead, with the Colombian Zapata lashing in the second moments later.
Furious Juventus coach Massimiliano Allegri was sent off after throwing his jacket onto the pitch after the second goal.
The Old Lady were not stirred into action, however, and failed to record a single shot on target in the first half.
Zapata pounced for his second in the final stages, taking his tally to 17 goals in his last 10 games across all competitions.
Elsewhere, Federico Chiesa scored a hat-trick as Fiorentina humiliated AS Roma 7-1 to reach the Coppa Italia semi-finals on Wednesday.
Chiesa, the 21-year-old Italy forward, sliced Roma open at will, hitting the post early on and striking twice in the first 18 minutes.
Aleksandar Kolarov pulled one back for the visitors but Luis Muriel restored Fiorentina’s two-goal lead before the break.
Eusebio Di Francesco’s Roma completely collapsed in the second half with Chiesa completing his hat-trick, Giovanni Simeone scoring twice and Marco Benassia also finding the net.
Substitute Eden Dzeko was sent off for the visitors after arguing with the referee to complete a woeful night for the visitors.
Stefano Pioli’s Viola will face Atalanta in a two-legged semi-final. (Reuters/NAN)