Strong choices were made by Portuguese coach Paulo Fonseca, who decided to leave the aces of the left flank,Theo Hernandez and Rafael Leao, on the bench.
The new Rossoneri signing, English striker Tammy Abraham, on a costly loan from AS Roma, sat on the bench.
In any case, the home team started better with prolonged possession of the ball through which they tried to find a gap in the not very solid defense of the guests.
However, in the ninth minute, it was the Rossoneri who found the net for the temporary advantage on the developments of a corner kick.
New signing Strahinja Pavlovic swooped in on the corner taken by Christian Pulisic, who exploited his considerable size, taking advantage of a less than optimal exit by the opposing goalkeeper who got in the way of one of his teammates.
This advantage reestablished a certain balance in the phases of the game that saw the guests begin to manage the ball possession with greater ease, compared to the first ten minutes of the match, and thus raising, although not by much, their center of gravity of action.
After the goal, it was the Rossoneri who threatened with two chances created by Pulisic and then Noah Okafor, without however finding a way to shoot cleanly.
Thus ended the first half with AC Milan temporarily in the lead.
The second half resumed without changes by Paulo Fonseca whereas Lazio coach Marco Baroni made substitutions aware of the weak points of the Rossoneri's defensive phase that needed to be addressed to bring the match back to equilibrium.
However, the second half reproduced what was shown at the beginning of the match.
Lazio managed ball possession for a long time without too many disturbances, ending up crushing the visiting team in the final meters of their own half.
Despite the obvious difficulty of the AC Milan defenders, no tactical move was adopted that could stem the explosive runs of the Lazio players on the left side of the field, where the difficulty from Emerson Royal and Samuel Chukwueze was evident.
In fact, in the space of a few minutes, in the 62nd and 66th minute after, two goals arrived from the home team.
First, the Argentine striker Valentin Castellanos scored and then the Senegalese striker Boulaye Dia.
Both found the net by finalizing a practically identical play with the left back Nuno Tavares as the protagonist, one of the best of the match.
Only with the result completely reversed did coach Fonseca decide to intervene on his formation.
So, after more than seventy minutes of play, Theo Hernandez, Yunus Musah, Rafael Leao and Tammy Abraham all came on together.
The newcomers, within a few seconds of their introduction, organized the equalizer with Leao, who controlled the ball and then quickly kicked towards the goal finding the net.
The last minutes of the match showed good intensity from both teams who tried to win without being able to seize the opportunity.
The match between Lazio and Milan ended in a draw, after a first half that saw the Rossoneri take the lead with Pavlovic, in the second half a one-two by Castellanos, Dia turned everything around. Fonseca decided to turn the team around and the substitutions immediately found the equalizer . In the final minutes of the game, Zaccagni and Abraham come close to scoring.
The draw means the two teams split a point each with Lazio moving to four points, while Milan arrives at the break with only two points.