Kean was subjected to racist abuse by Cagliari fans on Tuesday but his 84th-minute effort on Saturday helped Juventus edge closer to their eighth successive Serie A title.
Speaking on the club’s official website, Allegri said of the 19-year-old forward: “He is doing very well, but let’s leave him to be calm.
“He needed to stay at Juventus to grow technically, train and play with the champions, but he can also improve mentally.”
Krzysztof Piatek gave Milan the lead, becoming the league’s joint-top goalscorer, before a penalty from Paulo Dybala levelled the scores after an hour.
Kean’s late intervention means Juventus are 21 points clear at the top of the table, with second-placed Napoli having just eight games left.
Allegri added: “It was important to win today, now we just need a win or a draw, in the event that Napoli does not win all the matches.
“In the first half there was little or nothing, we were a bit ‘arranged’ and I knew we could have had some difficulties.
“We were more orderly in the second half, with a good game plan, we rearranged the layout.”
Fourth-placed Milan have gone four games without a win but boss Gennaro Gattuso was satisfied with his side’s showing at the Allianz Stadium.
He told Sky Sport Italia: “It was our best performance of 2019, we lost it in the final 18-20 minutes not because Juve did well, but because of our mistakes.
“These things can happen when you play the kind of football we do.
“Even last season, we had a great performance here and the biggest regret was we were naive.”
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