CBS is gaining on NBC on Thursday nights, and you can blame an unlikely culprit. After its two highest-rated seasons ever, NBC's "Friends" is suddenly taking a big dip at a time when NBC's Thursday hold is more tenuous than ever.

   Last week the show averaged a 9.2 18-49 rating, its best showing since week three but still down 17 percent from its average for the first three weeks and down a startling 39 percent from its year-ago showing.
   Paired with a resurgence of CBS’s “Survivor,” which also airs Thursdays at 8 p.m., that has meant very bad news for NBC, which for the first time in more than 15 years is in danger of losing its Thursday domination among adults 18-49.

   Last week CBS tied NBC for No. 1 on Thursday night for the first time during a November sweeps since the people meter’s inception in 1987. That came two weeks after CBS won the night outright against a slate of original NBC programming, albeit a win that was aided by Fox’s competing World Series coverage.

    The Thursday problems, of course, started with “Coupling’s” inability to hold an audience out of “Will & Grace,” but last week the failure of “Friends” to attract attention for what should be a huge bon voyage became increasingly evident.

   “Survivor,” on the other hand, hit a season-best 8.1 last week, up 7 percent from its six-week season average.

    The “Friends” ratings dropoff has come in the four weeks since the show wrapped up the Rachel-Joey love storyline, suggesting that perhaps it was abandoned too quickly. “Survivor’s” ratings uptick – the past two weeks have been its highest rated – comes after producers stuck in a controversial rule change that returned booted contestants to the competition.

   “Survivor” still lags well behind the 8.5 season average from last season’s “Survivor: Thailand,” though that includes the finale audience in its average.

   But as long as it’s pushing “Friends,” that dropoff doesn’t matter too much. “Friends” will assumedly pick up viewers as the year goes on, but by then CBS may have gotten several more Thursday night wins as “Friends” goes to      December reruns and “Survivor” takes advantage.
   Boosted by its Thursday showing and Wednesday's Country Music Awards, CBS tied NBC in 18-49s for the week for the first time during November sweeps since 1987.
  In other ratings news last week, the death episode of ABC’s “8 Simple Rules For Dating My Teenage Daughter” finished No. 5 with a series-best 8.1 18-49 rating. That also boosted lead-out “According to Jim” at 9 p.m. Tuesday to a best-ever 6.0.

   The premiere of NBC’s “Average Joe” finished No. 19, bettering the last showing by former Monday 10 p.m. occupant “Third Watch” by 66 percent.

    In the battle of made-for-TV sweeps stunts, CBS’s “Elizabeth Smart Story” finished ahead of NBC’s “Saving Jessica Lynch” by a mere 4 percent Sunday.