“Glee” did not fall completely off the map Thursday, but with originals from “Grey’s Anatomy” and “Person of Interest” now in the mix, it was much less successful.

The fourth season musical comedy dropped to a 2.5 adults 18-49 rating with 5.9 million viewers. That put FOX’s series in third for the timeslot, behind “Grey’s” (4.3, 11.5 million) and “Person of Interest” (14.3 million).

The new timeslot, which puts “Glee” directly against demo-friendly “Grey’s Anatomy,” was always going to be a challenge, and the fact that “X Factor,” though pretty consistent on a weekly basis (3.2, 9.2 million this week), is not providing the massive lead-in support some originally expected only makes that challenge more daunting.