He is a tracksuit-wearing chain-smoker and former bank employee, but Maurizio Sarri certainly won't feel intimidated when he leads Napoli against the mighty Real Madrid of French legend Zinedine Zidane.
"He's a master, an extraordinary coach," Arrigo Sacchi, who orchestrated AC Milan's unprecedented run of success at home in Europe in the 1990s, said of the 58-year-old Italian coach.
On the surface, the differences between the coaches as they prepare to meet in Wednesday's Champions League last 16 clash in Madrid couldn't be more striking.
Zidane is a former World Cup winner who played for some of the world's top sides including Juventus and Real before taking over the helm of the 11-time European champions.
The highest Sarri reached as a player was Serie B, and until 1999 he was still overseeing transactions between major institutions while working for the Italian bank Monte Paschi.
When Zidane hit a spectacular left-footed volley to secure Real's ninth Champions League with victory over Bayer Leverkusen in Glasgow, Sarri was trudging the touchlines trying to lead Sansovino through the Italian regional championships.
It was only in 1999, while Zidane was playing for Juventus, that Sarri decided football, not finance, would be his breadwinner.
"I chose the only job that I could do for free," Sarri explained in a 2014 interview to La Repubblica newspaper.
But what credentials he lacks Sarri makes up for with a passion and knowledge that allows him to squeeze every last drop from his players.
Former Napoli striker Gonzalo Higuain last season continuously paid tribute to Sarri for pushing him to target his new Serie A record of 36 goals as Napoli finished second in Sarri's first season in charge.
This term, Napoli lead Serie A on goals scored with 57 in 24 games, 16 of which came from makeshift striker Dries Mertens, who has hit three hat-tricks since moving out of midfield to replace injured Poland striker Arkadiusz Milik.
Zidane's team of 'Galacticos', one of the world's most expensively-assembled side, are unbeaten in 11 consecutive Champions League games.
But Sarri is a wily operator who is adept at coming in under the radar. And sharp-suited ex-players who played a better level of football than he did hold no fear.
Sarri doesn't wear a suit, smokes up to four packets of cigarettes a day and, unlike his famous peers, doesn't do football diplomacy.
"Higuain would really be an asshole if he didn't win the Ballon d'Or," Sarri said candidly last season.
In the same campaign, Sarri copped a two-game touchline ban for calling former Inter Milan coach Roberto Mancini, like Zidane a player-turned-coach, a "poof".
Sarri accepted the punishment, but was unrepentant: "It just came out," he said. "I could just as well have called him a Christian-Democrat."
But to believe Sarri crass or uneducated would be wide of the mark. Off the pitch he is a keen reader of literary works by John Fante, Charles Bukowski and Mario Vargas Llosa.
On it, he is passionate about the simple geometry of football, dead ball situations and where, exactly, his players should be positioned. He was one of the first in Serie A to use drones to film training sessions.
"Sarri is a perfectionist," defender Kalidou Koulibaly told AFP. "He's obsessed by the defensive line, our position. If you're one metre off where you're supposed to be in training, he stops everything.
"I quickly learned to stop punting the ball out from defence. The first few times, he came to me and said 'stop, stop, stop. With me, no one plays the ball out like that! We play football, we can make some mistakes but we try to move the ball out cleanly'."
As they prepare to take on Real, big things will be expected of Napoli's offensive line of Mertens, Lorenzo Insigne and former Real forward Jose Callejon in a match fans throughout the world are waiting to see.
But Sarri won't be fazed. He is likely to walk out from the Bernabeu tunnel as he did somewhere in the south of Italy 15 years ago: wearing a tracksuit with pockets big enough for a packet of 20.