Newcastle dominated the first half as the sides went in goalless at the break.
But the hosts finally made their dominance count through a stunning Fabian Schar strike from distance.
Callum Wilson then wrapped up the points with his third opening day goal for the club in a row.
5. Matt Targett - 7
Linked up well with Saint-Maximin down the left while also keeping Forest at bay comfortably. Photo: Getty
6. Bruno Guimaraes - 8
At the heart of most things Newcastle did well, particularly in the first half. The ball looked as though it was glued to his foot at times as the hosts controlled large parts of the game. Photo: Gualter Fatia
7. Joe Willock - 8
Had several chances before but brought some real energy to the midfield with good touches and forward thinking runs. Was plucky in winning the ball back for Newcastle on numerous occasions. Photo: Stu Forster
8. Joelinton - 8
A midfield powerhouse as he bullied the opposition physically despite being sloppy on the ball at times. Could have scored a fine goal following a charging run into the box. His low cross assisted Wilson’s goal to put the game to bed. Photo: Stu Forster