A goal by Caldirola sent Palladino's Monza into ecstasy, who took back Inter in the last breath of the first Serie A derby played in Brianza.
And in the final he even came close to winning.
The consequences are paid by Inter who had only reopened the championship on Wednesday by stopping Napoli and who are now losing two points which risk weighing on the run-up for the Scudetto.
Ready to go and in the ranks of Monza, Pablo Marì is back on the field as owner, after the stabbing suffered in Assago at the end of October.
For the Spaniard, already on the field for a segment in Florence, command post in the center of the defense next to Armando Izzo and Marlon, with the new players Machin and Birindelli.
For Inter, Lukaku on the bench at the start to make way for the Dzeko-Lautaro duo, with Acerbi again preferred to De Vrij.
A little over a minute goes by and Darmian slips past Carlos, enters the area and with his left foot engages Di Gregorio in a miracle, whose importance is only frustrated by the offside flag that goes up.
Live match, because on the reversal in front Mota breaks through and then gets in the way of two steps with Izzo on the next cross.
Carlos, on his 24th birthday, perseveres in the error already made at the start, only this time Darmian passes behind him, but also deposits the advantage on the net.
Not even the time to cheer before Inter is restarted: Pessina unloads in the area, Ciurria picks it up and makes it 1-1 with a left-footed lap.
It's only been 11 minutes.
Monza would also have the ball for overtaking, with Petagna who does not head down Machin's cross from two steps away.
But at 22'
At the change of pitch, Lautaro sinks from the left, ball for Darmian and Dzeko misses the tap in.
All a few seconds before the relay with Lukaku.
But Monza have the merit of reacting and playing the game at the start of the second half.
Ranocchia also tries, who first tries to serve Gytkjaer, then with a set piece from distance.
Inter fell asleep, Monza showed they wanted to reopen the match: Pablo Marì headed in and was stopped by Onana, but then Inter could triple up in the final.
Acerbi headed in from Asllani's free-kick, but Gagliardini's foul on Marì stopped play.
Then another Lautaro show, with a serpentine and right foot that caresses the outside post.
Yet the finale needed the twist: cross from Ciurria, Caldirola headed off and, thanks to a detour from Dumfries, made it 2-2.
Caldirola himself, with time running out and still in his head, frightens Onana.
Galliani rejoiced in the stands as in his Milan days: the way the final went, his derby was won on points.