The Náxara game plan lasted barely 20 seconds, the time it took Juliano Belletti's side to open the scoring through their new frontman, who wasted no time settling any early nerves in front of a home crowd watching via Barça Play. Ghanaian winger Aziz supplied the assist, and Quer finished with a precise, crossed strike that gave the visiting goalkeeper no chance.
The early goal did little to change the pattern of the game, with Barça Atlètic lining up in a classic 4-3-3 that completely dominated a Náxara side content to sit deep and search for isolated counter-attacks.
The hosts came close to a second soon after when a cross from Éder Aleix Caicedo found Aziz, who somehow failed to convert from close range, but the pressure told before half-time when Quer struck again, this time finishing off another assist from his fellow forward to make it 2-0.
Although both of the opening goals came down the right, Barça Atlètic also created plenty down the left through the combination of Caicedo, Orian Goren and Dutch winger Shane Kluivert, who had two notable chances of his own before the interval.
The second half followed a similar script, with Náxara continuing to sit in and rely on defensive resilience, though the home side never let up and continued probing for further goals without needing to force the issue.
Quer completed his hat-trick with a well-placed finish from a knockdown by Orian, before Álex González added gloss to the scoreline with a spectacular strike to make it 4-0. There was still time for one final twist, as Quer picked up an unorthodox rebound from the goalkeeper's clearance to complete his personal tally and make it 5-0, rounding off an unforgettable full debut for the Barcelona academy graduate.
The result gives Barça Atlètic, coached by Belletti, the perfect start to their Segunda Federación campaign, with Quer's four-goal haul an emphatic statement of intent from a player who arrived with a proven scoring record from his previous spell at Hospitalet.
It was the first-ever competitive meeting between the two clubs, and one that Náxara will want to forget quickly as they prepare for the challenges ahead in the third tier of Spanish football.