Zlatan Ibrahimovic gave Milan the lead against Inter then decided to wind up Romelu Lukaku. It backfired horribly.
"You want to speak about my mother?"
Romelu Lukaku was seething. A yellow card and a stern talking to from referee Paolo Valeri having done nothing to lift the red mist.
Inter's diminutive playmaker Nicolo Barella attaching himself to Lukaku's torso in a bid to calm the powerhouse striker was one of the more memorable sights of an action-packed first 45 minutes in this Milan derby for a place in the Coppa Italia semi-finals.
Or the Derby della Madonnina, to give the game its full, grander title. A game that takes its name from a pristine golden statue of the Virgin Mary.
It seemed for all the world that Zlatan Ibrahimovic had not spoken about Lukaku's mother with such reverence.
Here was Milan's 39-year-old talisman, who suggested the youthful make-up of the Serie A leaders' XI was a factor in their 3-0 weekend defeat to Atalanta, deciding to display his own brand of leadership in the guise of juvenile schoolyard bully.
Ibrahimovic's crowing chuckle as mayhem unfurled around him (Arturo Vidal got involved - of course he did - for no apparent reason) was one of a player who had recently enjoyed a familiar feeling for the 499th time in his career.
Freed from shackles of their knife-edge Scudetto battle, both teams played with freedom and the intent to land a psychological blow. The fact each team had the same idea appeared to irritate all concerned, but it made for great entertainment.
It is doubtful Antonio Conte would consider such a cavalier selection in league combat as he rolled out on Inter's left flank here. Ivan Perisic was at wing-back, paying as much attention as you'd expect to the part of his position lurking after the hyphen.
That increased the defensive burden on Aleksandar Kolarov on, a defender who has worn 11 for the bulk of his career. Kolarov's shirt number is a statement of particular intent.
Ibrahimovic showed he recognised that point of weakness in the 13th minute, when he leapt athletically to meet a Rafael Leao cross, knocking Perisic and Kolarov to the ground in the process. Brahim Diaz was just unable to turn home.
Kolarov still seemed distracted when he backed off enough for the former Sweden international to fire though his legs and beyond Inter goalkeeper Samir Handanovic.
The script seemed written, goal 500 was surely on the way to take Ibrahimovic closer to yet another piece of silverware. Why not have some fun and wind up the opposition's star man.
Ibrahimovic's language and his message seemed appalling, with ESPN footage showing him at one point appearing to yell: "Go do your voodoo s***, you little donkey."
A flaw in the plan to rile Lukaku was the yellow card that Ibrahimovic received for his part in the spat. Not a problem in itself, but in the 58th minute he clumsily and needlessly fouled Kolarov to collect a second booking.
Displaying none of his vast experience, Ibrahimovic had gone from hero to villain to idiot within half an hour of playing time.
And so, it was over to the youngsters and backup players who the star striker sometimes seems to consider walk-on extras in his one-man show.
First there was on-loan defender Fikayo Tomori, who was quickly disabused of the notion he had escaped chaos by leaving Chelsea this week. Thrust into a debut by Simon Kjaer's first-half injury, he made a brilliant last-ditch block to deny Lukaku.
Alessio Romagnoli and Theo Hernandez defended heroically down the Milan left but reduced numbers forced willing attacking players back to man unfamiliar barricades. Leao was pressed into action and brought down Barella. After consulting the pitchside monitor Valeri pointed to the spot.
Lukaku has been known to roll his penalties home. On this occasion, he tested the structural integrity of the crossbar and the ball ricocheted into the turf and home. Then there was a shouting match with a team-mate (Yes, Vidal; nope, no idea).
Enough mayhem? Nonsense. Valeri had to limp out of the action injured. Fourth official Daniele Chiffi looked like he was putting on the microphone and headset for the first time in his life and 10 minutes of stoppage time were required.
In the seventh of those, wantaway midfielder Christian Eriksen curled home a sumptuous free-kick, leaving Ciprian Tatarusanu no chance to add to his fine catalogue of eight saves.
Last act for Eriksen? Maybe. Definitely last laugh for Lukaku.
Ibrahimovic likes to call himself a lion but Tatarusanu and the Milan players he left behind were the lions here, roaring defiantly at wave after wave of Inter attacks before buckling at the last. Nine of Inter's 27 shots were blocked.
After fatefully dwelling too long in self-parody at the end of the first half, Ibrahimovic owes them an apology, and surely Lukaku is also due one. Perhaps they shouldn't hold their breath.