Mauro Icardi's last-gasp penalty in extra-time forced a shoot-out, but Radja Nainggolan missed as Lazio knocked out Inter Milan to reach the Coppa Italia semi-finals on Thursday.
Lucas Leiva converted the decisive penalty for a 5-4 win at the San Siro after the match had finished 1-1 following extra time.
Ciro Immobile had broken the deadlock after 108 minutes when he blasted in following an exchange with Felipe Caicedo.
But there was more drama with Inter awarded a contested penalty after 125 minutes when Sergej Milinkovic-Savic fouled Danilo D'Ambrosio.
Inter skipper Icardi cooly slotted in with the last kick of extra-time to revive home hopes.
But Lazio goalkeeper Thomas Strakosha saved Lautaro Martinez's penalty in the shoot-out and got his fingers to Nainggolan's kick before Leiva scored the winner.
Lazio will play AC Milan over two legs in the semi-finals, after Gennaro Gattuso's side beat Napoli 2-0 in the San Siro midweek.
The second semi-final will see Fiorentina, who crushed Roma 7-1, take on Atalanta, 3-0 winners over four-time defending champions Juventus.
The semi-finals will be played over two legs on February 27 and April 24.