There are two tactical approaches in the world of football that have been opposing each other for about 20 years: the Spanish-influenced 'tiki-taka' and Italian football's idea of counter-attacking and a impenetrable defense.
Two totally different ideas on how to play the game but both completely effective in their own right.
Tiki-taka, which is a style of play characterised by short passing, movement and dominating possession, is often associated with the likes of Spain and Barcelona.
While the Italian football's approach has been perfected by Juventus in years gone by. It's ugly but very effective as shown by Max Allegri's team this season in which they have kept 15 clean sheets in 23 matches.
Napoli represents the most cheerful and colourful exception of European football because it refuses to accept tiki-taka or Italian football.
In their Champions League encounter on Tuesday, Frankfurt will have to deal with two of Europe's most in-form players, Khvicha Kvaratskhelia and Victor Osimhen, who have made Napoli one of the favourites to win the tournament with their stunning performances in the Serie A so far.
Napoli's intense style of play and their pressing high up the pitch is comparable to that of Jurgen Klopp's Liverpool in years gone by, given they aggressive and are constantly running for the full 90 minutes.
Domestically, Napoli and manager Luciano Spalletti are flying high in a league full of teams struggling both on and off the pitch.
Napoli plays with a very Dutch 4-3-3 formation, which includes attacking wingers that support Osimhen and which make every attacking action deadly.
With the exception of Maurizio Sarri's Lazio, all the other top Italian top teams play with a 3-5-2 or with a 3-4-2-1 like Juventus, Milan, Inter and Roma.
It's a choice that demonstrates how many of Italy's top teams have stubbornly refused to change their ways and progress, while Napoli have adopted the progressed with attacking and positive football.
At this moment, Spalletti finds himself in the upper echelons of Europe's best coaches, alongside Klopp and Pep Guardiola.
Should Liverpool decide to move on from Klopp, who is currently struggling in his seventh season at Anfield after winning everything there is to win, Spalletti would be seen as the ideal candidate to replace him.
Spalletti is a professor who doesn't have a jacket and tie, who loves the countryside and relishes spending time at his farmhouse in Tuscany.
His football is a combination of old and modern theories and has employed ideas from Zdenek Zeman – the Czech-Italian coach renowned for his exciting, offensive tactics mainly in the 4-3-3.
While he has adopted the ideas of Zeman, Spalletti is a more defensively-minded manager while his intense training session ensure his players remain fit for the full 90 minutes in every match.
Another key element to how Napoli have dominated this season is Spalletti's use of his very physical but adept No 9 Osimhen, who links the whole forward line together.
Napoli's 2-0 win over Salernitana in January also saw Spalletti hit an historic landmark in the Serie A.
It was Spalletti's 276th win in the Serie A, the most in the Italian top-flight. It is staggering record which demonstrates the ability of a coach who has overcome many peaks and troughs in a managerial career that saw him spend five years at Russian side Zenit Saint-Petersburg before returning to Italy to take up spells at Roma and Inter Milan, with the latter he was sacked from.
And now at Napoli, the team's morale is as high as can be.
In their most recent training session, Spalletti picked up a loose ball and started dribbling between the players, showing enthusiasm to the applause of midfielder Stanislav Lobotka and the number of fans in attendance.
Napoli are at the top of European football because it has a number of brilliant players – but also a squad who have discovered the joy of playing football again thanks to the atmosphere created by Spalletti.
But with the attention back on tonight's opponents, Frankfurt face a tall order if they are to shock one of Europe's most in-form teams.
The Europa League champions will have to create a huge blockade to prevent free-scoring Napoli from getting through.
If Frankfurt aren't careful, they could find out exactly why Real Madrid have made Georgian winger Kvaratskhelia one of their top targets.
The 22-year-old has an impressive 10 goals and 12 assists in 19 games in the Serie A this season – making him the best Georgian player to have ever played in Italy.
Kvaratskhelia has the speed and physical strength of Figo and the ability to handle the ball with elegance and precision of David Beckham.
His childhood idols have become a point of reference and fittingly they are the players he resembles most.
Kvaratskhelia, who played at Rubin Kazan and Dinamo Batumi before joining Napoli last year, is the youngest player among European football's elite to reach double figures in both goals and assists in the league.
Only Erling Haaland, Kylian Mbappe, Neymar, Lionel Messi, Mohamed Salah, Robert Lewandowski, Harry Kane, Marcus Rashford and Randal Kolo Muani have a better ratio.