Seeking to reignite a ratings turnaround that faltered last year, ABC won the first week of the new broadcast season as the No. 1 U.S. network in prime time, figures from Nielsen Media Research showed Tuesday.

Buoyed by such hits as Grey's Anatomy and Dancing with the Stars, ABC came in as the most watched network overall for the week ending September 30 and tied with NBC for first place among viewers aged 18 to 49.

The 18-49 ranking, signifying the group most prized by advertisers, was important in particular for NBC, which has struggled to shake off its own three-year long ratings slump. It comes with an asterisk, however.

NBC benefited from a Nielsen rule change that allowed it to add viewers to last Monday's season premiere of Heroes from a Saturday replay of it.

The return of Grey's Anatomy ended up as the week's highest-rated single show in the 18-49 demographic. Going head to head with ABC's hit medical drama, the premiere of CBS cop series CSI garnered the week's biggest total audience.

ABC had the most watched new series so far this season with Private Practice, but NBC's sci-fi action remake, Bionic Woman, was No. 1 in the 18-49 race.

The broadcast networks were in a holding pattern for much of last week, as hefty DVR viewing of premiere-week programs made it harder to determine viewership levels and the true success or failure of the new slates.

On Thursday, 55 million watched the "Big Three" at 9 p.m. That fell to 38 million at 10. This is like due to DVR usage of nearly 20 percent.

Clearly, not all of those declines can be attributed to delayed DVR use. While the viewership numbers are expected to be positively impacted somewhat, the added viewers are not expected to change the rankings of the new and returning shows.

CBS' internal online panel of viewers showed, for example, that an equal number of viewers recorded both CSI and Grey's Anatomy, Thursdays at 9.

In a head-to-head battle at 9 p.m. Wednesday, ABC's Private Practice, the Grey's Anatomy spin-off, and NBC's Bionic Woman drew 14.5 million and 13.5 million live-plus-same-day viewers, respectively.

Those numbers made them the most successful frosh premieres.

Meanwhile, The CW, whose shows got a ton of pre-season critical acclaim, was struggling. Gossip Girl, which received considerable buzz among younger demos, premiered on September 19 with a disappointing 3.5 million viewers, and fell sharply against stiffer competition on September 26.

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.