"The only thing I can say is it was sad to see the crowd's response when he was getting hurt, man," Newton said of the tweaked hamstring that sidelined Manziel, per ESPN's David Newton.
"I just think it was classless at that time. Anytime a person is hurt, you don't celebrate. I've had that done in my career. It takes the integrity out of the game."
Manziel's early departure capped another shoddy start for the rookie under center. Johnny Football threw for just 32 yards while failing to generate more than a field goal.