Fast National ratings for Friday, March 16, 2012.
 
CBS' NCAA Tournament coverage -- including Lehigh's thrilling upset win over Duke -- won Friday night easily, delivering a smaller overall number than the network is accustomed to, but a better number among young viewers.
 
Among adults 18-49, CBS averaged a 2.2 rating, beating ABC's 1.5 rating in the key demographic. FOX averaged a 1.1 rating, beating the 0.8 rating for NBC and The CW's 0.6 rating.
 
Overall, CBS averaged 6.2 million viewers and a 3.9 rating/7 share, which edged out ABC's 3.8/7 and 5.76 million viewers. NBC was third with a 2.8/7 and 4.08 million viewers, better than FOX's 1.8/3 and 2.64 million viewers. The CW's 1.61 million viewers and 1.0/2 trailed.
 
8 p.m. - ABC won the 8 p.m. hour overall with the 6.09 million viewers for "Shark Tank," which finished second with a 1.7 rating among adults 18-49. CBS' NCAA hoops coverage was second overall with 5.36 million viewers and won the hour with a 1.8 key demo rating. NBC's "Who Do You Think You Are?" averaged 4.24 million viewers for third and a 0.7 key demo rating for fourth. The CW's "Nikita" averaged 1.53 million viewers and a 0.5 key demo rating.
 
9 p.m. - With the big upset pending, CBS' basketball coverage leapt to 8.375 million viewers and a 2.9 rating among adults 18-49. ABC was second with 5.57 million viewers and a 1.5 key demo rating for "Primetime: What Would You Do?" A repeat of "Grimm" averaged 3.39 million viewers and a 0.7 key demo rating for NBC compared to FOX's 2.65 million viewers and a 1.1 key demo rating for a "Kitchen Nightmares" repeat. The CW's new "Supernatural" averaged 1.69 million viewers and a 0.7 key demo rating.
 
10 p.m. - ABC moved back into first overall for the 10 p.m. hour with 5.62 million viewers for "20/20," which was second with a 1.4 rating among adults 18-49. CBS' basketball averaged 4.86 million viewers and won the hour with a 1.8 key demo rating. NBC's "Dateline" was third with 4.6 million viewers and a 1.0 key demo rating.
 
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change.