Multi-network coverage of the NFL Draft, including Fox’s primetime coverage, contributed to dizzying drops for primetime heavyweights on Thursday night.

Fox’s 8-11 PM three-hour coverage (1.1, 5.83M) nearly doubled its last week Live + Same Day performance, scored collectively by Gotham and Showtime at the Apollo.

Among those hit, ABC’s Quantico (0.5, 2.76M) opened its third season at 10 PM, matching its series low, and down 50% from last season’s premiere. In total viewers Quantico slid by 24%. Network’s previous low in the hour this season had been a 0.8 demo rating suffered by How To Get Away With Murder, and Scandal.

Against the stiffer competition, CBS’ The Big Bang Theory (1.9, 11.52M) tumbled 21% compared to last week’s 2.4 which had equaled the sitcom’s previous series low. Nonetheless Big Bang easily topped Thursday, both in demo and total viewers, followed by lead-out Young Sheldon (1.7, 11.01M). Mom (1.3, 8.46M), and Life in Pieces (1.0, 6.29M) also won their slots.

ABC’s 8 PM Grey’s Anatomy (1.4, 6.46M) fell 18% compared to previous week, which had been the series’ low, after which Station 19 (0.9, 5.17M) slid to a season-low 0.9.

NBC’s Chicago Fire (0.9, 5.41M) took the hour, also besting CBS’ S.W.A.T (o.8, 5.25M), inching up in total viewers while coming within 1/10th of previous week’s demo. Chicago Fire was NBC’s best performer of the night, self-starting out of Champions (0.4, 1.53M), which was flat week to week. NBC kicked off night with Superstore (0.7, 2.85M), AP Bio (0.5, 1.77M) and Will & Grace repeat (0.4, 1.78M).

CBS (1.3, 7.96M) took the night, followed by Fox (1.1, 3.83M) in the demo and ABC (1.0, 4.79M) in total viewers. NBC (0.6, 3.12M) followed, then CW (0.4, 1.20M) with steady showings for Supernatural (0.4, 1.48M) and Arrow (0.3, 0.91M).