A plastic container comprises an upper portion including a finish adapted to receive a closure, a lower portion including a base, and a sidewall extending between the upper portion and the lower portion. The upper portion, the lower portion, and the sidewall define an interior volume for storing liquid contents. The plastic container further comprises a pressure panel located on the container and moveable between an initial position and an activated position. The pressure panel is located in the initial position prior to filling the container, and is moved to the activated position after filling and sealing the container. Moving the pressure panel from the initial position to the activated position reduces the internal volume of the container and creates a positive pressure inside the container. The positive pressure reinforces the sidewall. A method of processing a container is also disclosed.