Title hopefuls Milan made a sluggish start to the new year with an underwhelming first-half display in Sardinia, although Cagliari would have been equally frustrated by their failure to capitalise on promising openings before the break.
Right-back Marco Palestra dragged his early effort harmlessly wide after he got in behind the Milan backline. Michel Adopo then registered the game’s first shot on target with a tame header just past the half-hour mark, before Luca Mazzitelli slashed wide at the near post.
After being left off by Cagliari’s poor finishing, Milan briefly thought they had a chance to go ahead when the referee pointed to the spot on the stroke of half-time, only for the decision to be overturned for an offside in the build-up.
As it proved, Milan required just five second-half minutes to break the deadlock after being fired up by Massimiliano Allegri’s wise words at the interval.
Adrien Rabiot was the architect with a precise low cross to Leao, who controlled at the far post and then thumped it past Elia Caprile to net for the sixth time in 10 Serie A appearances against Cagliari.
That proved to be Leao’s last meaningful act in the contest before he made way for Niclas Fullkrug to make his Rossoneri debut following his arrival on loan from West Ham United.
Fullkrug was not presented with a chance to score, but he nearly marked his Serie A bow with an assist when he played in fellow substitute Christian Pulisic, whose driven effort was beaten around the post.
Caprile was then required to dive low to his left to keep out Luka Modric’s low curling free-kick. As a result of the goalkeeper’s late stops, Milan had to be content with a narrow win as they extended their unbeaten streak to 16 league games (W11, D5) and ended Cagliari’s three-game unbeaten home run.
Flashscore Man of the Match: Rafael Leao (AC Milan)