Pep Guardiola and Maurizio Sarri have had vastly different careers, but they may be more similar than you think.
When Pep Guardiola won his first Champions League with Barcelona in 2009, Maurizio Sarri was at lowly Perugia in Italy.
When the former won his second Champions League two years later, Sarri was at Sorrento - the ninth club of what appeared to be an archetypal journeyman's career.
He was sacked at Sorrento, too. As Guardiola was lauded, immortalised by his successes with one of club football's greatest teams, Sarri was unemployed and anonymous.
If he had been told then what awaited him in October of 2017, he would likely have laughed in derision. Sarri is 58 now, hardly a youthful coach, but it feels very much like he has only just emerged as one of the game's shrewdest minds.
In truth, he had always been talented. He needed a break and he got it with Empoli. He guided the Azzurri to Serie A - the first time he had reached the top flight as a manger - and impressed Aurelio De Laurentiis enough to get the Napoli job.
There were doubts upon his arrival; who was this bespectacled, unfashionable nobody? No reputation or proven success, his appointment was dismissed by Napoli's deity, Diego Maradona.
But now there are no such question marks. Sarri has established himself as one of Europe's best, and on Tuesday night he comes face to face with perhaps the best.
It's an astonishing ascent. For this unassuming, unheralded former banker to be facing Guardiola, as an equal, would have been inconceivable only a few years ago. “I am happy to do this for a living,” he said when he first arrived at Napoli.
“If next year I started again from the bottom of Serie A or even Serie B, I’d be just as happy. I hope not to change too much." He hasn't changed.
In that sense, he and Guardiola could hardly be more different. For the Catalan, there was no such struggle to reach the top; he got there almost immediately with Barcelona.
In appearances and demeanour they differ vastly too. Guardiola with his pressed shirts, v-neck jumpers and expensive shoes, his designer stubble and pensive, cool persona; Sarri with his loose fitting tracksuit, receding hairline and glasses, chain smoking on the sidelines.
Yet, oddly, there are parallels between the two. Both are meticulous, almost obsessive thinkers, both seem to battle with their emotions during matches and both have been praised immeasurably for the style of football their respective sides produce.
There are also tactical similarities. Guardiola has admitted City and Napoli are "similar", in that they are both attractive, free-flowing attacking sides that comfortably top Europe's goalscoring charts this season.
But Sarri's emphasis on the importance of positions, the synchronicity of Napoli's build-up play, the high-pressing and the fluid attacking movements can all be compared to that of Guardiola's City. "Napoli can kill you with high pressing," Guardiola has said. So can City.
Then there's Sarri's use of Dries Mertens, for so long a solid but unspectacular winger until his transformation in a false 9 role. Since then he's been prolific, and though the circumstances were different, it brings to mind Guardiola's insdecision to employ Lionel Messi as a false 9 back in 2009.
These are two coaches with considerable ingenuity, devoted to their craft and not afraid to innovate, to experiment in their pursuit of effective but equally aesthetic football.
Sarri was nicknamed ‘Mister 33’ by his players at Sansovino, his club from 2000 to 2003, when he allegedly prepared 33 varying set-piece routines for use in attacking situations. “We used four or five of them in the end,” he later admitted. It was not an uncommon level of detail.
For Sarri detail is crucial, as it is for Guardiola, as it is for many of the game's most intelligent coaches. And that is what Tuesday's meeting promises; an evening of intricate, elaborate and nuanced football.
On the surface Sarri and Guardiola may appear almost the antithesis of each other. Their respective career paths suggest the same. But there is far more than meets the eye when it comes to Sarri, a coach whose rugged exterior can often belie the nature of his Napoli side.