The moment the teams stepped out of the tunnel, the world dissolved into a dizzying kaleidoscope of color and a deafening wall of sound.
The San Siro, shared by both clubs, was a beast of two hearts tonight.
One half was a roaring sea of AC Milan's red and black, the Curva Sud, a fortress of flags and flares.
The other half was Inter's Curva Nord, a pulsating wave of blue and black, equally loud, equally passionate. The noise was so intense it felt like you could breathe it in.
On the pitch, the pre-match handshakes were a tense affair. Theo Hernández, Milan's fiery left-back, shared a brief, intense stare with Inter's Denzel Dumfries, a promise of the physical battle to come.
In the center circle, Lautaro Martínez and his Milan counterpart, Davide Calabria, exchanged a firm, respectful handshake, the calm in the eye of the storm.
Leon found himself near Mohammed Kudus.
The Ghanaian winger was bouncing on the balls of his feet, a bundle of kinetic energy.
