The Italian coach thinks that the Sweden international's sending off was correct and says that his side put in a good performance against the San Paolo club despite the scoreline
The Serie A holders were reduced to 10 men near the hour mark after Ibrahimovic lost his head and slapped Salvatore Aronica as he placed his right arm around the back of team-mate Antonio Nocerino.
Ibrahimovic is now facing the prospect of a lengthy ban as a result of his action, but Allegri has guaranteed he is not afraid to learn the number of matches that the Swedish striker will have to miss.
"I am pleased with [referee Nicola] Rizzoli," Allegri told Sky Sport Italia. "I had not seen anything at the time, but after watching it on TV Ibra deserved to be sent off.
"I am not worried about his absence, regardless of the fact that he is a key player for us."
Despite Milan picking up just one point from the match, Allegri noted he was satisfied with his side's display.
"It was important to turn in a good display against a team that was able to cause us problems," he explained.
"Then we were reduced to 10 men, but we did not stop playing. This point has allowed us to recover the spirit that we must have to target the Scudetto.
"Of course that we have to improve in certain situations, but we did not run many risks, even when we were a man down."
Milan failed to take advantage of Juventus' goalless draw against Siena, but Allegri the difference between his side and the Bianconeri, who still have one game in hand.
"Juve arenot breaking away, because they are just one point ahead," he added. "Even if they win that other match, the gap is not a concern."