With the 2007-08 TV season now a week old, ABC and NBC have emerged as front-runners in the ratings race after both networks rolled out their big guns to capture viewers.

ABC, which relies on female-friendly fare including Grey's Anatomy, Dancing with the Stars, and The Bachelor, appeared to have edged the more masculine NBC - which features power performers such as Heroes and Bionic Woman in its lineup - in the 18-49 demo race by a tenth of a ratings point in the first week of the season. However, NBC claimed victory based on a technicality; a Nielsen rule change has permitted the network to count two airings of Heroes - one a repeat - together. That rule change is under review after scathing criticism from NBC's competitors.

The standout performances from opening week include CSI on CBS, which pulled a whopping 25.2m viewers on Thursday to take the most-watched crown and a demo win, Grey's Anatomy with 20.9m viewers and a 17% demo share, Heroes, which had a stunning 17m viewers and a 17% demo share, and Bionic Woman, which bowed with an impressive 13.9m viewers and 14% demo share.

ABC was greatly assisted by leveraging the pulling power of Dancing with the Stars to give new shows strong lead-in numbers. The US version of Strictly Come Dancing, now in its fifth season, started with 21.3m viewers on Monday and performed equally well on Tuesday and Wednesday.