The 19-year-old has two Champions League goals and one Ligue 1 strike to his name in his past six competitive outings, after earning a spot in Laurent Blanc's side due to an injury to Thiago Silva.
The former Brazil Under-17 representative said he has defied his own assessment of his ability, scoring against Olympiakos Piraeus, Toulouse and Benfica.
"I didn't know I could do that. In youth teams, I scored some goals but since I turned pro, be it at Corinthians or Roma, I had never scored," the teenager told Ligue 1.com.
"It's magical what's happening with PSG.
"Right from my first game, despite not having played for four months, I scored my first goal.
"It's a moment I'm going to remember forever. And then, almost straight after, I scored two more important goals."
Marquinhos, formerly of Italian club Roma and Brazilian outfit Corinthians, said Blanc - an ex-defender himself - encourages his stoppers to get forward and impact the scoreboard.
"It's so new for me I didn't know how to celebrate... I was a bit lost," Marquinhos said.
"More than the joy it brings, it also gives me confidence. I needed that.
"He (Blanc) encourages the defenders to go into the opposition box for set-pieces.
"It's something he really wants to develop and which should become our trademark.
"He shows us how we should position ourselves, which runs to make."
Get the best features, fun and footballing frolics straight to your inbox every week.
Thank you for signing up to Four Four Two. You will receive a verification email shortly.
There was a problem. Please refresh the page and try again.