I Rossoblu began the game in mid-table, knowing that they didn't even manage a league goal against their opponents last season, but were also armed with the knowledge that they had beaten them at San Siro as recently as May 2025, albeit in the Coppa Italia.
With two wins, two draws, and two losses from their last six matches, Raffaele Palladino and his squad were going to have to come up with a season's best performance if they wanted to earn all three points.
Palladino had made two changes to his starting XI, one less than Ruben Amorim, who will have been looking for a reaction similar to the weekend win at Udinese (after the Rossoneri's recent loss to Bournemouth in the Europa League).
Three goals in the first 26 minutes
The Portuguese coach won't have been happy with how his team started the game, as even before Samuel Mbangula had put the visitors into an eighth-minute lead, Bologna had already had two efforts at goal.
Ominously, Milan hadn't won any of their last eight games when falling behind first, and so with 82 minutes left to play, their assignment became even more crystal clear.
Whatever Amorim had barked in the aftermath of that opener appeared to have worked, as Alphadjo Cisse equalised just five minutes later.
Cisse would bag his and Milan's second on 26', and in between his brace, Milan had seen a remarkable 69% of the ball.
Fikayo Tomori was a colossus at the back for the hosts, attempting four tackles in the first half alone - more than anyone else on the pitch - and keeping the likes of Nadir Zortea and Federico Bernardeschi at bay.
Pervis Estupinan would also weigh in with four tackles of his own, whilst Strahinja Pavlovic's winning of 10 of his 14 duels was well ahead of anyone else.
The pendulum swings
Bologna were knocking the ball around well despite being behind, Rahim Alhassane enjoying a perfect 100% pass completion, closely followed by Lewis Ferguson's 92.2% and Samuel Mbangula's 90%.
If the visitors were going to lose, they would at least go down fighting.
Mbangula, Bernardeschi, Zortea and Jens Odgaard were starting to get some joy when Bologna attacked, and the quartet all had at least four touches in the Milan box, with Odgaard also having two shots at goal early in the second half.
A flurry of substitutions from either side appeared to have an effect on the balance of play, with the visitors soon in the ascendancy.
Bologna take control
Right on the hour, Davide Bartesaghi was forced into an own goal, and just two minutes later, Mbangula put his side ahead once more.
It was the first time since May 23 that Bologna had scored three in a Serie A match, and on that occasion they'd drawn 3-3 with Milan's city rivals Internazionale.
The pendulum had swung to such an extent that the hosts went over half an hour without an attempt at goal, and their frustrations became clear with a 10th foul given against them with 20 minutes still to play.
Though the likes of Ferguson, Zortea and Odgaard were winning less than half of their one-on-ones, they were making a nuisance of themselves in the midfield areas, and that was stopping Milan from playing their natural game.
Modric at his brilliant best but an opportunity missed by Milan
Luka Modric did his utmost to drag his side back into the match, and his 97.5% pass completion was in keeping with what we've come to expect from the Croatian.
He was a big part of why Milan had 80% of the ball in the closing stages, but by then, the visitors had shut up shop, and, as a result, the hosts only had Francesco Camarda's shot to show for their attacking efforts.
When Mbangula made it four for Bologna in the 86th minute, that was the cue for the stadium to start emptying out, and despite a late flurry from Milan, they couldn't find a way past Christian Comotto again.
Arguably it wasn't for lack of trying, given that Ardon Jashari, Koni De Winter and Strahinja Pavlovic had had 339 touches alone between the three of them.
Milan and Amorim had effectively tried everything to break down a defence that held firm, despite only needing to make one successful tackle all game.
A definite opportunity missed by the Rossoneri.