The Sweden striker scored twice to eclipse Alejandro Bedoya's early opener and send PSG top of Ligue 1.
Ibrahimovic revealed after the game that he is still working his way back to full fitness amid an ongoing struggle with a heel injury.
And midfielder Matuidi feels Ibrahimovic being in good condition is key to PSG's ambitions this term.
"For sure, he had a complicated start of the season because of his long injury," the Frenchman said. "He is back at the right time with us, doing what he does best - scoring goals.
"We are happy to see him scoring two goals. We know when Ibra is in good shape, in most cases, Paris win.
"It is good to have him back and I hope he will carry on like that."
Ibrahimovic now has eight goals in nine league appearances this season.
The 33-year-old's next assignment will be to help his current club overcome his former employers when PSG head to Barcelona in the UEFA Champions League on Wednesday.
PSG simply need to avoid defeat in order to secure top spot in Group F.
