He does not make the headlines very often but he has quietly become the best midfielder in Serie A and a Champions League force
The Champions League's Group C brought together two forwards who, on current form, rank among the very best on the planet. With Liverpool's Egyptian hitman Mohamed Salah on one side and irrepressible Paris Saint-Germain star Neymar on the other, the first round was supposed to be a foregone conclusion for their respective sides.
That Group C enters this fifth match-day as one of the most open pools in the entire competition is testament to the fight and resolve shown by Napoli in taking points off the two favourites. It is also a positive reflection on one man in particular.
Napoli's Brazilian steam-roller Allan has already kept both Salah and Neymar firmly in his pocket during this gripping Champions League phase, and if he can maintain his fine form for just two more matches, the Italians should clinch a shock spot in the last 16.
Despite plying his trade in Serie A for the best part of seven seasons – he spent three years at Udinese before moving to the San Paolo in 2015 – Allan has long flown under the radar.
While he does not lack talent or flair on the ball, he is not as showy as some of his compatriots, preferring to forage for possession in the middle of the pitch and move it on to a more attack-minded team-mate.
Now, however, people are starting to stand up and pay attention, thanks in no small part to his performances in silencing the fearsome attacks of Liverpool and PSG in three unbeaten outings – two draws against the French champions and a tense 1-0 win over the Reds in Italy.
Indeed, Allan received his first cap last week against Uruguay and, true to his reputation, barely allowed a single shot from fearsome Celeste duo Luis Suarez and Edinson Cavani in a tense 1-0 victory for the Selecao.
“He deserved it, we had been monitoring him for a long time,” Brazil coach Tite said of Allan's overdue debut.
“Allan is good in transition, going box to box, leading counterattacks and breaks. He’s mobile and brings protection defensively.”
Such proficiency has naturally led to comparisons with Arturo Vidal, once considered one of the world's premier box-to-box midfielders. In his intensity, work-rate and not insignificant talent, Allan is living up to that heady praise, even if the man himself is reluctant to acknowledge it.
“The Vidal comparisons? It is true that we are a bit similar, we have similar styles of play,” the Brazilian told Goal.
“I must continue to work hard, I’m happy that people are pleased with how I’m playing.”
With Vidal seemingly on a downward slope and restricted to brief – yet still effective – cameos at Barcelona, Allan has everything necessary to succeed the Chilean to his title of king of the roving midfielders.
First things first, though. Napoli must avoid a potential banana skin in the shape of Red Star Belgrade on Tuesday, while keeping half an eye on the result of PSG's meeting with Liverpool over in Parc des Princes.
If the Italians can pass their Serbian assignment, their fate will be in their own hands for the matchday-six trip to Anfield; and another impeccable 90 minutes from the in-from Allan would take them several steps closer to what had initially appeared an extremely unlikely place in the last 16.