In Brian Williams’ first complete week as the titular anchor, “NBC Nightly News With Brian Williams” did ratings business as usual, winning key categories on all five weeknights and finishing with a lead of more than 1 million average viewers over second-place “ABC World News Tonight.”

According to data from Nielsen Media Research for the week of Dec. 6-10, “Nightly News” averaged 10.54 million total viewers to place first for the 23rd consecutive week and to maintain a lead of more than 1 million viewers for the sixth consecutive week over “World News Tonight,” which averaged 9.475 million viewers. “CBS Evening News” averaged 7.30 million viewers.

“Nightly” also ranked No. 1 among the 25- to 54-year-old viewers targeted by news programming, averaging a 2.5 rating in the demo, 12 percent ahead of “World News” and 40 percent ahead of “Evening News.”

After the previous week, when Tom Brokaw ended his long reign Dec. 1, producing a seven-year-high tune-in of more than 15 million viewers, the “Nightly” ratings slipped back toward the newscast’s season-to-date level of 10.4 million viewers, which is up 1 percent year to year. “World News” is averaging 9.1 million, down 6 percent year to year. “Evening News'” season-to-date average of 7.2 million viewers is off 9 percent compared with the same weeks in 2003.

ABC News pointed out that “World News” was the only newscast to show week-to-week growth, picking up 10,000 viewers in Mr. Williams’ first week compared with the week of NBC’s big switch, while “Evening News” lost 410,000 viewers.