AC Milan have been provisionally awarded the quarter-final tie against Inter Milan after it was abandoned amid ugly scenes of crowd trouble.
The game was halted in the 73rd minute after Inter fans threw flares, one of which hit keeper Dida on the shoulder.
The trouble started when Inter, 3-0 down on aggregate after Andriy Shevchenko's first-half strike, saw Esteban Cambiasso's effort ruled out.
Play resumed for 30 seconds after a 20-minute delay before being abandoned.
Uefa is likely to confirm on Wednesday that the tie will be awarded to AC Milan, while Inter can expect to face severe sanctions by European football's governing body.
The game had got off to a controversial start after Shevchenko appeared to headbutt Marco Materazzi in the second minute.
Neither the referee, Markus Merk, or his assistant spotted the offence so Shevchenko remained on the field.
Should Uefa investigate Shevchenko's headbutt on Materazzi, the AC Milan forward could be charged with violent conduct which could rule him out of both semi-final legs.
Shevchenko appeared to deliberately clatter into Materazzi, setting the tone for a fractious opening period.
When the game did settle, Inter pressured AC Milan's defence with Adriano causing Alessandro Nesta all kinds of problems with his physical presence.
Indeed, Nesta was booked for a foul on Adriano which means he will miss the next match.
Where Nesta failed, Jaap Stam was immovable and the Dutchman had another outstanding game, thwarting Adriano at every move.
Shevchenko scored a superb goal
Inter's best efforts came from long range with Juan Sebastian Veron and Kily Gonzalez forcing superb saves from Dida, who was also in imperious form.
At the other end, Toldo's only real action of the first half was picking the ball out of his net after Shevchenko's superb left-foot strike from the edge of the area.
Inter's chances of getting back into the match were always going to be limited given that they had not beaten AC Milan in three years.
And they suffered a further setback when Adriano limped off soon after the break.
His replacement Obafemi Martins almost made an immediate impact, but Dida's outstretched leg diverted his shot onto the post.
Inter continued to press for the equaliser and they thought they had go it when Cambiasso headed home Veron's corner with 20 minutes left.
But referee Merk deemed that Dida had been fouled in the build-up to the goal and awarded a free-kick.
That decision sparked bottle and flare-throwing, and Dida was struck on the shoulder, the firework only missing his head by inches.
While the goalkeeper received treatment in the middle of his own half, Inter's Cristiano Zanetti and Veron tried to clear the AC Milan penalty area of the missiles but to no avail.
Merk instructed the players to leave the pitch. After a lengthy delay, both sides came back on, only for the restart to last 30 seconds before Merk abandoned the tie completely.
The referee will now submit his report to the Uefa Control and Disciplinary Body, who will deal with the case.
Inter Milan: Toldo, Cordoba, Javier Zanetti, Favalli, Materazzi, Cristiano Zanetti (Cruz 46), Van der Meyde, Veron, Gonzalez (Mihajlovic 46), Cambiasso, Adriano (Martins 50).
Subs Not Used: Carini, Ze Maria, Karagounis, Vieri.
Booked: Gonzalez, Cordoba, Cambiasso.
AC Milan: Dida (Abbiati 73), Cafu, Maldini, Nesta, Stam, Seedorf, Pirlo, Ambrosini, Shevchenko, Crespo (Rui Costa 68), Kaka.
Subs Not Used: Kaladze, Pancaro, Serginho, Brocchi, Tomasson. Booked: Ambrosini, Nesta.
Goals: Shevchenko 30.
Agg (0-3): Abandoned - due to crowd trouble
Ref: Markus Merk (Germany).