This is according to a note in Wikipedia:

The name "Super Sentai" was introduced in the 1979 series Battle Fever J. Originally, Gorenger and its successor JAKQ were not included as Super Sentai series. In episode 1 of the 1989 series Turboranger, when it honored the past ten Super Sentai series, Battle Fever J was listed as the first Sentai. It was not until the 1995 series Ohranger that Gorenger and JAKQ were included as the original first two series.

Quite interesting, it'd be great to check if other sources inform the same thing about it.

Source: http://en.wikipedia.org/wiki/Gorenger

by Marcos Silvestri