#3 Frenkie De Jong vs Fabian Ruiz
Fabian Ruiz has been one of the most consistent performers for Napoli in what has been a turbulent season for them and, though he did not touch the heights of the 2018-19 season, he has certainly improved certain aspects of his game this year.
He does not get on the scoresheet himself that often but has a good eye for threading key passes, finding spaces and dictating the play for his team.
He usually assumes a No.10 role behind Napoli's three-man attack and thus will often find himself in a duel with Barcelona's Frenkie de Jong.
With Sergio Busquets and Arturo Vidal suspended for the game, the hosts will rely heavily on the talented midfielder for breaking up opposition play and for his impressive distribution skills to find Messi, Suarez or Griezmann in dangerous positions.
Both these players are pass-masters, with Ruiz having a 90% pass success across all competitions and De Jong completing 91.6% of his passes. They are rarely booked and rely on their technical skills to outwit their opponents.
#2 Nelson Semedo vs Lorenzo Insigne
Attacking down the wing has been one of the strengths of Napoli this season. Well, for the last few seasons, thanks to the consistency of Callejon and his partner on the left-wing, Lorenzo Insigne, they have been very effective attacking from the wide positions.
Insigne was crucial to Napoli's success at the Coppa Italia and will be hoping to provide the same kind of service to his club in the Champions League.
He will face Nelson Semedo on the wings, who has shown an improvement in his game and mentality since the La Liga restart in June. On his day, the Portuguese right-back can wreak havoc on the right flank with his blistering pace and crossing abilities.
He has struggled with consistency in his time at the Camp Nou and that can prove costly against a player like Insigne, who likes to cut inside from the left and can beat defenders with his pace, skills and ball-control.
#1 Gerard Pique vs Dries Mertens
Gerard Pique and Dries Mertens have both achieved iconic status at their respective clubs. Pique has established himself as one of the most successful defenders in Barcelona's history, while Mertens became the all-time top scorer for Napoli this season.
The Belgian forward scored the opening goal in the previous meeting between the two clubs and could've easily added to his tally if not for an unfortunate injury in the second half. Thus Pique will have to be on high alert in the upcoming fixture as Mertens will be looking for another goal to add to his impressive tally.
While Pique does have an advantage over the Napoli forward when it comes to aerial duels, Mertens is very agile for a striker and with his low centre of gravity, pace and good close control can easily get past the Pique, who has seen a significant loss in pace over the last few seasons.