The pair could be seen and heard exchanging insults as Lukaku had to be restrained by his team-mates as he attempted to confront the Swedish forward.
Ibrahimovic, who had given Milan a first-half lead, was sent off after picking up a second yellow card, after the break before Christian Eriksen scored a stoppage-time winner for Inter to send them through with a 2-1 win.
The heated altercation between the former Manchester United teammates began before the half-time whistle of the quarterfinal match which Inter won in the San Siro.
CORRECTED AUDIO | 😳
Listen to the insults exchanged between Romelu Lukaku and Zlatan Ibrahimovic in last night’s Milan derby.
Shocking words from both players now that the audio is clearly audible.#SportyIssues
— Sporty Issues (@Sporty__Issues) January 27, 2021
AC Milan will defend Zlatan Ibrahimovic if he faces disciplinary action for racism after the Swede clashed with Inter’s Romelu Lukaku, team technical director Paolo Maldini said on Saturday.
“We are ready to defend Ibrahimovic in any way possible if racism should be brought up, which has nothing to do with him,” said Maldini.
“It happens to argue, it’s an ugly episode to watch, but it ends there.
“(Ibrahimovic) was sorry for having left the team with 10 (players). He defended his teammates against Lukaku’s unprovoked attacks.”
Ibrahimovic spoke out against racism on Wednesday, writing on Twitter: “In Zlatan’s world, there is no place for racism.
“We are all the same race — we are all equal!! We are all players some better than others.”
Both players were booked over the incident; Ibrahimovic was subsequently sent off in the second half after picking up a second yellow.
They will both be suspended for their team’s next Italian Cup game; with Lukaku picking up a yellow card in the previous game.
The Belgian will miss next Tuesday’s Italian Cup semifinal, first leg tie against Juventus