For the first time since late 2005, CBS' "Late Show with David Letterman" has beaten NBC' "The Tonight Show" in total viewers for a week of original broadcasts, putting both networks into spin mode.

For the week ending June 19, "Late Show with David Letterman" averaged a 2.5 rating/6 share overall to go with an average of 3.46 million viewers per night. "The Tonight Show with Conan O'Brien" averaged a 2.3/6 and 3.32 million viewers for the same period.

The last time "Late Show" beat "The Tonight Show" in viewers for an all-first run week was back in December of 2005, when Oprah Winfrey's appearance gave David Letterman a boost.

Needless to say, CBS is very excited about this victory. Not surprisingly, NBC has a very different perspective.

NBC's ratings release boasts that O'Brien beat Letterman "in every important demographic -- adults, men and women 18-34, 18-49 and 25-54 -- on every night of the week.

Indeed, "The Tonight Show" averaged a 1.3 rating in the 18-49 demographic and averaged an estimated 1.8 million viewers in the demo, compared to 1.1 million viewers for "The Late Show." In viewers, that's a 67 percent victory margin, which is pretty big, right?

Well, CBS' spin is that "The Late Show" trailed "The Tonight Show" by only 0.5 ratings points this week, compared to 0.6 last week and 1.4 for O'Brien's premiere week. That's still massive, percent-wise, but clearly dwindling.