A hot fill type plastic container includes a finish, a bottom and a main body that is generally rectangular in transverse cross-section. The main body has an upper dome portion, a lower label portion and a waist groove defined between the upper dome portion and the lower label portion. Both the upper dome portion and the lower label portion have front and rear surfaces as well as opposing side surfaces that are narrower than the front and rear surfaces. The opposing side surfaces of the upper dome portion have a substantially vertically oriented reinforcing element defined therein that is recessed with respect to the surrounding sidewall of the upper dome portion. The reinforcing element extends into the waist groove, which increases the flexibility of the dome portion above the waist groove and protects the dome portion against damage as a result of contact with other containers during the filling and packaging processes.