It took just six minutes for the visitors to break the deadlock, with Luka Modric floating a quick free-kick over the defence to Pulisic, who beat the offside trap and slotted into the bottom corner.
It was a nightmare start for Kosta Runjaic’s men, who had lost five successive league fixtures for the first time since 2018 coming into this clash, yet they responded well.
They went close to an equaliser when Hassane Kamara had a 25-yard drive saved, while Fikayo Tomori should have done better with a strike that went wide at the other end.
That was a rare chance for the Rossoneri, as the hosts continued to threaten.
Mike Maignan was by far the busier of the two goalkeepers, and he was on hand to thwart Mergim Vojvoda from long range.
Jesper Karlstrom also had a 25-yard daisy-cutter saved, while numerous moves broke down in the final third due to an unwillingness to cross the ball into the box.
Le Zebrette, therefore, still had work to do, and they remained dangerous after the break as Vojvoda had another go from outside the box, this time dragging off target.
Ruben Amorim’s men then broke forward themselves, with Pulisic denied by Maduka Okoye at his near post, and that signalled a switch in momentum as Milan doubled their advantage midway through the half.
Omari Hutchinson pounced to convert the rebound after Okoye could only push Ardon Jashari’s low strike back out into the six-yard box.
The goalkeeper did better with his next stop, somehow getting a hand to Goncalo Ramos’ effort from point-blank range and pushing it onto the bar.
Keinan Davis, who had blazed an earlier opening out for a throw, then tested Maignan for Udinese, before Giulio Vinciati - making his Serie A debut - burst forward and dragged past the far post.
Milan, though, were able to see out the game and avoid a fourth successive away league draw, also moving into the UEFA Champions League qualification spots.
Udinese, meanwhile, are outside the relegation zone only on goal difference and have now lost four consecutive head-to-heads at Stadio Friuli.
Flashscore Man of the Match: Christian Pulisic (AC Milan)
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