Call it a Bionic breakdown? NBC's Bionic Woman might need a tune-up after losing one-fifth of its premiere-week audience.

The retro-fitted remake averaged 11.1 million viewers (26th place), per the latest Nielsen rankings.

That was a better showing than all but two new fall series, but it was a far worse showing than the nearly 14 million viewers Bionic Woman had for its debut.

Among the networks' prized 18- to 49-year-old viewers, it didn't have any better luck. Bionic Woman fell from 8th to 19th, placing below such trendsetters as ABC's Brothers & Sisters and Extreme Makeover: Home Edition.

Private Practice (17th place, 12.4 million), Bionic Woman's Wednesday night rival, slipped, too, but not nearly as badly or as far as the NBC show.

The Grey's Anatomy spinoff lost 2 million viewers, but just two places in the 18-49 rankings, down to 11th place, from the Private Practice premiere.

NBC and ABC's losses were CBS' gain, which saw Criminal Minds (10th place, 14.6 million) add nearly 2 million viewers who had trouble remembering when their favorite show was back with new episodes.

The CBS series evidently had its own trouble remembering to tell youngsters to watch — the show continued to run third in the 9 p.m. Wednesday hour, behind both Private Practice and Bionic Woman.

Continue reading more about Private Practice ratings...

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