Prior to the 87th minute, Milan looked destined to leave Genoa with a drab draw. Even with Pulisic and Rafael Leao in the match as second-half substitutes, Milan never quite got going for nearly the entirety of the match.
That was until Musah floated a cross into the box in the game's final moments, allowing Pulisic to create his moment of magic and win all three points.
The goal wasn't without controversy, as both sides waited on a VAR review after celebrations subsided. Pulisic, though, was deemed to have controlled the ball off his chest, not his hand, as the goal stood.
That was only the start of the chaos, though, as, in stoppage time, AC Milan goalkeeper Mike Maignan was sent off with a straight red card for a collision outside of the box. Olivier Giroud was forced in goal, as Genoa hit the ensuing free kick off the crossbar.
In the ensuing scramble, though, Genoa goalkeeper Josep Martinez earned a dismissal of his own, making him the second goalkeeper to be sent off in the match. In the end, though, Milan were able to hold on, with Giroud making a late save before being mobbed by teammates in celebration.
With the win, Milan go top of the league, two points ahead of rivals Inter and four points ahead of Juventus, who sit in third.