NAPLES, Italy — When Dries Mertens scores Napoli’s first goal, Stadio San Paolo’s creaking stands rattle and shudder with the noise. It is not a cheer: a cheer is something joyful and merry and high-pitched. This is different: deeper, more guttural, rooted as much in release and euphoria, caught somewhere between a roar and a howl. It hits you like a wave.

In the commotion, Mertens runs to one corner, pursued by his teammates. In another, Daniele Bellini counts to three. Briefly, he clenches his fist in celebration. Then he walks to his iPhone, mounted on a tripod, and turns on the camera. He draws his microphone from his back pocket, pauses for a second, and takes a deep breath.

And then he places the microphone to his lips, and his voice cuts through the noise.

“Gol per il Napoli,” he announces, drawing out that first ‘O’ over five seconds. “The scorer” — a pause — “wearing the No. 14” — and another, he is shouting now – “Dries!” The crowd answers, 50,000 voices booming into the sky: “Mertens!”

Bellini repeats the call and response again and again, 10 times in all, building to the finish. He rocks backs on his heels, crouches down, heaves in his breath. He announces the name as he leaps back up, stretching it out to two syllables: “Dri-Es!” The fans do the same, a great wave of sound crashing around this crumbling concrete ruin of a stadium. “Mer-Tens!”