Bitter rivals Inter’s victory on Saturday over Udinese left the hosts needing to win to stay within striking distance, and they were the dominant side in the first half here.
Nevertheless, they struggled to create many clear-cut chances, instead being frustrated by a resolute visiting backline.
The hosts started well, with Alexis Saelemaekers curling a shot wide of the post and Matteo Gabbia heading over, while Rafael Leao thought he had broken the deadlock with a clever dinked finish before seeing the linesman’s flag raised for a clear offside.
Against Lecce’s relatively high defensive line, Milan’s strategy was clear as they continually tried to play the ball into the space behind. However, Lecce’s offside trap worked a treat, with Leao caught out on several occasions.
The Rossoneri did have an opening shortly before half-time when Christian Pulisic forced Wladimiro Falcone into the only save of the first half, while the away team offered nothing besides a Nikola Stulic flick that flew well over the bar.
After the break, Milan upped the ante and started to threaten more regularly. Another pair of Gabbia headers went narrowly over the crossbar, while Pervis Estupinan was not far away from troubling Falcone with a speculative volley from distance.
The Lecce goalkeeper was worked for the second time in the match shortly after, getting down well to push Samuele Ricci’s low drive behind for a corner, and he needed to produce an even better stop to parry Pulisic’s effort from inside the area to safety.
Adrien Rabiot was next to go close, shooting first-time over the crossbar while unmarked in the area.
Eventually, though, Massimiliano Allegri’s team found the goal they were looking for through substitute Niklas Fullkrug, who only had to head home from five yards after being found by a perfect Saelemaekers cross.
With Lecce unable to put their opponents under any pressure, Milan were able to see out the game comfortably to secure a crucial win.
Unbeaten in 10 games at the San Siro, they remain well in the fight for just a fourth Scudetto this century. Lecce, meanwhile, remain in the relegation zone and have now not beaten Milan since 2006.
Flashscore Man of the Match: Alexis Saelemaekers (AC Milan)
