Both of the teams entered the clash looking to boost their respective European hopes. However, while Lazio remain in the UEFA Champions League hunt, Milan must first catch Bologna in the UEFA Conference League spot, and their defeat to the Rossoblu in midweek didn’t do them much good.
Early on, it was the visitors who were the most threatening, and Mike Maignan needed to be alert to keep out Boulaye Dia inside the opening three minutes. The Lazio striker then headed wide before Gustav Isaken fired an attempt past the post as the visiting outfit set out their stall.
Only a Yunus Munah last-gasp challenge stopped Dia from testing Maignan again when one-on-one, although replays were inconclusive as to whether he actually did intervene.
Following that effort, Milan finally sprung into life themselves when Tijjani Reijnders drew a stop out of Ivan Provedel.
However, Lazio were soon back on top, and not long after Maignan denied Isaksen, the Biancocelesti were in front.
A quick break found Adam Marusic and, while Milan’s goalkeeper got a hand to that attempt, he could only push it into Mattia Zaccagni’s path for a simple finish.
Following the restart, Samuel Gigot saw a shot saved by Maignan, while Joao Felix hammered over the bar at the other end.
Milan started to exert some sustained pressure on the Lazio goal, but their hopes of recovering from the deficit were dealt a significant blow when Strahinja Pavlovic was given a straight red card for bringing down Isaken when through on goal.
That decision initially knocked the stuffing out of the Rossoneri, and while they continued to push what they could forward in search of an equaliser, Provedel was something of a passenger.
However, after the introduction of numerous attacking players, one of them, Chukwueze, rose high to nod Rafael Leao’s cross in off the bar.
With the momentum, Milan went in search of a second goal, yet it was Lazio who struck the killer blow with almost the last kick of the game.
When Maignan felled Isaksen in the area, referee Gianluca Mangianello had little choice but to award a spot-kick following a trip to the pitchside monitor, and from 12 yards, Pedro made no mistake.
That last-gasp drama sees them leapfrog Juventus into fourth in what promises to be an enticing battle between the two sides for a spot in the Champions League.
Milan, meanwhile, will be devastated to lose in such fashion and now find themselves nine points adrift of the Rome-based outfit, with this their first defeat in their past nine Serie A home games.
They have now also lost three league games in a row for the first time since February 2023, which will only crank up the pressure on manager Sergio Conceicao.