ABC finished in a near tie for #1 on Sunday with a Masters Golf Tournament overrun-boosted CBS in Adults 18-49 (1.6/5 vs. 1.7/5), beating Fox by 23% (1.3/4) and NBC by 78% (0.9/3).
The Masters is not on Broadcast and not direct competition for ONCE.
The Masters was on broadcast (CBS) but ended at 7:15pm est. I don’t know if their post coverage ran into 60 minutes or not. I doubt it played much of a factor though. Ratings were down across the board last night probably because it was the first nice weekend for a lot of the country so people were probably out remembering what the sun is all and what not.