The Brazil international scored his first PSG goal at the Parc des Princes to help inflict Luis Enrique's first defeat as Barcelona coach.
Luiz struck the opener before Lionel Messi levelled with Marco Verratti and Blaise Matuidi putting the home side 3-1 ahead.
Neymar pulled a goal back for the Spanish giants, but it proved in vain as PSG won for the first time in Europe this term after a stuttering start to Ligue 1 that has seen them draw five of their eight games.
However, Luiz - a close-season target for Barca who has regularly attracted criticism over his flamboyant approach to defending - is hopeful the result can spark the Ligue 1 champions' season into life.
"Everyone was saying bad things about me – that's normal when you’re not playing well. But [against Barca] it was a dream come true - my first goal for PSG against a great club. I'm very happy," he told Canal+.
"Hopefully it changes the season for us. We were not playing well but we've achieved a great victory and hopefully this can get us going.
"It was a great night. A great atmosphere, a Champions League game, two great clubs, great players.
"It's a dream to be here. I love this club."
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