To prevent inertial forces from inadvertently releasing the slide of a semi-automatic pistol into battery, a slide stop retention mechanism is mounted on the frame. A finger extends from the mechanism and pivots under the force of a biasing spring into engagement with the slide stop when the slide is in the open position. The finger supports the slide stop. A force applied to the slide stop, either manually or via a cam on the slide when the slide is pulled back and released, will move the finger out of its supporting position and allow the slide to move to battery.