The ground where fellow Argentina great Diego Maradona achieved some of his most memorable exploits and where the player he is often compared to is still revered with god-like status.
Just ask Alcide Carmine, the owner of a coffee bar in downtown Naples that features an altar dedicated to Maradona.
"For us, Maradona is more than a man. He's a god. We Neapolitans love soccer and live for soccer," Carmine said in an interview over an espresso. "We can never forget what he did for us."
The altar inside Bar Nilo features what is claimed to be a strand of Maradona's hair inside a rotating, transparent box. It's labeled "miraculous hair."
Carmine took possession of the hair in 1990 when he found himself on the same airplane as Maradona while returning from a Napoli away game.
"When he got up some of his hair was left on the headrest," Carmine said. "I kept it and then I had the idea to do this."
After leaving Barcelona — where Messi now plays — Maradona led Napoli to its only two Italian league titles in 1987 and 1990, plus the 1989 UEFA Cup. He also led Argentina to the 1986 World Cup title, scoring a goal with his fist against England in the quarterfinals that became known as the "Hand of God."
Napoli had never won anything significant before Maradona's arrival, and he was treated as a savior by a city lacking in basic social services.
"We saw with our own eyes the miracles that he created," Carmine said. "Other miracles are just stories."
Carmine got the idea of creating a shrine to Maradona from the vast array of small altars lining the dark alleyways of Naples — the candles of which used to help people find their way before the advent of electrical lighting.
Carmine wasn't the only Napoli fan inspired to express his devotion to Maradona by religious rites. A short walk from Bar Nilo lies Via San Gregorio Armeno, a narrow road lined with shops selling handmade figures for nativity scenes. Alongside baby Jesus, Mary and Joseph are figurines of Maradona and current Napoli standout Dries Mertens.
"One of the first figurines we made was of Diego Armando Maradona and you can imagine how many we sold. Still today, it sells a lot," said craftsman Marco Ferrigno, who runs the most prominent shop on the street.
"Diego left an indelible mark on the history of this city — in terms of both soccer and beyond soccer. He was someone 'sui generis,'" Ferrigno added, using the Latin term for someone in a class by himself. "We're still talking about him 30 years later."
While he doesn't like to admit it, the player whose figurine Ferrigno sells the most these days is that of Cristiano Ronaldo.
"There are a lot of Juventus fans around here," Ferrigno said. "They live in hiding."
Among current Napoli players, the best seller is Mertens, the crafty Belgium forward known locally as "Ciro" — the most popular of Neopolitan names.
"Ciro has really carved out a place in Neopolitans' hearts. He's like a 'scugnizzo' (Neapolitan dialect for a street kid) who was born in Belgium. Then he had second thoughts and returned to this city and now he's having the time of his life," Ferrigno said. "You have to understand that it's lucky being born in Napoli but it doesn't happen to many people. But then there are those people who discover, even if they were born in New York or in Belgium, that they belong here. Like (former Napoli captain Marek) Hamsik, too.
"Ciro's personality is really Neapolitan."
Mertens needs only one more goal to match Hamsik's record for Napoli players at 121 — six more than Maradona scored across all competitions with the club.
Before Hamsik concluded his 12-season stay at Napoli, he wrote a love letter to Naples in The Players' Tribune.
"In Naples, we don't just have one football manager. We have three million," Hamsik wrote in 2017. "Every man, woman and child knows what's best for Napoli. Every four-year-old boy at the park knows how we can score more goals. Every 90-year-old woman tending to her garden can tell you why we need to change our formation.
"That feeling … that passion, it's in their blood," Hamsik continued. "In Naples, football is like a religion, and the Stadio San Paolo is the church. Napoli is the only major club in the area, and Neapolitans feel part of it — because they are. Football is what they think about when we wake up, it's what they talk about all day, and it's what they dream about at night. Sometimes, football feels like it is the only thing that matters."
The way the local Catholic church is intertwined with Napoli only heightens the feeling that following the team is a religion.
Each year during preseason training in the northern region of Trentino, Cardinal Crescenzio Sepe, the archbishop of Naples, visits to bless the club with a Mass held on the practice field. The Mass concludes with other priests going up into the stands amid the fans to hand out Communion — thus converting the entire stadium into a church.
Asked in 2018 about Ronaldo's arrival at Juventus, Sepe responded with a reference to the Portugal standout's first name.
"(Juventus) can take all the Christians they want, but we're the real Catholics," Sepe said before putting on a personalized Napoli jersey over his clerical collar.
The catholic influence on Napoli is also evidenced inside the Stadio San Paolo — named for St. Paul according to the legend that the apostle docked in the Fuorigrotta area surrounding the stadium when he reached current-day Italy.
Lining the wall near the old entrance to the field are a series of devotional cards featuring images of catholic saints and Madonnas.
Before he climbed the steps and emerged before the crowd, Maradona used to pray to the Madonna di Pompei and kiss the prayer card.
While the entrance with the saints and Madonnas is no longer in use — the players now emerge at midfield instead of under the curva B (northern end) like when Maradona played — Messi might want to make a special stop there.
"We have a saying here, 'Abbi fortuna e dormi' (Those that have luck can sleep calmly at night)," Ferrigno said. "So luck is fundamental."