Conan O'Brien gets flying start on "Tonight" show

Host Conan O'Brien gestures onstage during the 58th annual Primetime Emmy Awards at the Shrine Auditorium in Los Angeles in this August 27, 2006 file photo.

LOS ANGELES (Reuters) - New "Tonight" show host Conan O'Brien got off to a roaring start in his first outing behind the desk vacated by Jay Leno last week after 17 years as America's favorite late night television chat show host.

Early viewing numbers that O'Brien's debut on NBC's "The Tonight Show" on Monday got a 7.1 rating in the nation's biggest media markets -- trouncing rival David Letterman on CBS and bringing in the biggest Monday edition "Tonight" show audience for more than four years.

That 7.1 rating compares to about 4.0 rating for a typical "Tonight" show this year but is below the monster 8.8 rating that Leno scored when he bowed out on Friday.

Total viewing figures will not be available until later this week.

Leno returns to NBC in the fall in a controversial move to the 10 pm prime-time slot five days-a-week that will save the ailing network millions of dollars over the cost of producing a drama series in that hour. NBC is currently bottom in audience rankings of the four major U.S. TV networks.

NBC said on Monday "The Jay Leno Show" will premiere on September 14. It will be the first ever entertainment program to be stripped across prime time on U.S. network television.

O'Brien, 46, more sketch artist than stand-up comedian, opened the show on Monday with guests Will Ferrell and rock band Pearl Jam.

Early reviews of his debut were mixed. The Hollywood Reporter called the show "a work in progress", while Entertainment Weekly called it a "large-scale, impressive debut. But we all know that success in late-night depends on the long haul."

(Reporting by Jill Serjeant; Editing by Bob Tourtellotte)