Playing centrally, Dembele had two early chances thanks to his wide men but saw one attempt headed away by Abdoulaye Ndiaye and another saved by Marco Bizot.
Khvicha Kvaratskhelia then passed up a golden opportunity to score his first PSG goal, completely missing the target after Fabian Ruiz had squared the ball to him. There was also a scare at the other end as Ludovic Ajorque’s strike from range fizzed marginally past the post.
Bradley Barcola then became the latest member of Luis Enrique’s front three to falter in front of goal when he hit the post, before Fabian saw his attempt cleared.
Undeterred, Les Parisiens remained patient as they continued to work the ball well, and moments after a brilliant Ndiaye tackle had denied Dembele, Barcola raced behind Kenny Lala to tee up his fellow forward for a simple finish just before the half-hour mark.
Gianluigi Donnarumma was immediately called into action to retain that lead, getting down brilliantly to deny Romain Faivre, and the goalkeeper made another impressive save to stop Lala’s dipping shot seconds before the break.
Donnarumma was left helpless after the restart, though, as Willian Pacho’s awkward header from Lala’s cross saw the ball bounce invitingly for Romain Del Castillo to effortlessly stroke it into the bottom corner.
Despite Barcola sending an instinctive shot marginally wide, parity didn’t last long as a long Marquinhos ball forward caused havoc that culminated in Dembele sliding the ball past Bizot and going ahead as Ligue 1’s top-scorer.
He completed his hat-trick just six minutes later, applying a clinical first-time finish to Lee Kang-in’s incisive pass, but Ajorque renewed Brest hopes in the 71st minute when the striker turned away from Pacho and curled his shot out of Donnarumma’s reach.
Shortly after that, Mahdi Camara came agonisingly close with his glancing header and Faivre saw a shot palmed away.
Desiré Doue then made a blistering run forward and teed up Goncalo Ramos for a simple finish to ensure PSG took all three points in their 14th consecutive match unbeaten across all competitions.
That puts them 13 points in front at the top of Ligue 1 ahead of Marseille’s match against Lyon on Sunday. In contrast, it’s back-to-back competitive defeats for Brest, who had salt added to their wounds when Ramos’ pass was cut out and the ball sat invitingly for him to tap it in.
Flashscore Man of the Match: Ousmane Dembele (Paris Saint-Germain)
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