NBC Nightly News was the most watched evening newscast the week as David Muir made his official debut as anchor of ABC World News Tonight. Muir won the week in the news demo with ABC’s best delivery in 16 weeks. But DAVID MUIRBrian Williams’ NBC newscast took the younger demo, 18-49, despite ABC’s switch from Diane Sawyer to Muir. Muir’s opening week marked NBC’s widest 18-49 margin over ABC in five weeks.

In the atypical week, NBC and CBS’ stats are three-day averages, while ABC’s stats cover Tuesday through Friday. NBC’s newscast outperformed ABC’s in the news demo on two of the three nights they went head-to-head. On Thursday, NBC’s newscast was not rated due to the NFL game gumming up the network’s news broadcasts in western markets. That night — Thursday being the day of Joan Rivers’ death — newscast numbers jumped for ABC and CBS — particularly ABC.

For the week, ABC’s World News Tonight logged a winning 2.040 million news demo viewers, to NBC Nightly News’ 1.967 million and CBS Evening News 1.613 million.

NBC’s newscast logged 8.471 million viewers overall, besting ABC’s 8.265 million and CBS’ 6.497 million.