Updated

By Jill Serjeant

LOS ANGELES (Reuters) - The Vancouver Winter Olympics proved a ratings triumph for beleaguered NBC, but popular comedian Jerry Seinfeld's new show stumbled with critics as the U.S. television network returned to regular programing.

NBC said on Monday that 190 million Americans watched the Vancouver Olympics on its stations and cable outlets over 17 days, making them the second-most-watched Winter games since Lillehammer in 1994.

The network, which has been bottom of the four big U.S. TV broadcasters for several years, said NBC's Vancouver cover drew 9 percent more viewers than the combined efforts of rivals ABC, CBS and Fox during more than two weeks of competition.

The prime time average nightly audience for the Olympics was 24.4 million compared to an average 22.3 million over the 17 days for ABC, CBS and Fox. The action in Vancouver also twice toppled Fox ratings king "American Idol," marking the first defeats of "Idol" in six years by any TV program.

Despite strong viewership, NBC has said it will lose about $250 million on its coverage after paying a record sum for U.S. broadcasting rights to the Olympics.

As the Vancouver games ended on Sunday, NBC launched one of its most-anticipated new shows, a comedy game panel called "The Marriage Ref" from the star of 1990s comedy series "Seinfeld."

The show is one of the highlights of NBC's hastily revamped lineup after it axed "The Jay Leno Show" in February in an embarrassing retreat from cheap-to-produce talk show fare at 10 p.m., traditionally seen as a time for expensive scripted dramas.

"The Marriage Ref," which has stars weigh-in on the lighthearted arguments of American couples, drew a strong 14.5 million viewers but some scathing reviews.

The Star Ledger's Alan Sepinwall called it an "ugly, unfunny, patronizing mess." Time magazine's James Poniewozik said it was "the most God-awful mishmash."

Sunday's show featured one couple arguing about stuffing their dead dog and another about whether to put a stripper pole in their bedroom. Seinfeld, who has done little TV since his old show ended in 1998, is executive producer and an occasional panelist on "The Marriage Ref".

Other reviewers were kinder and intrigued about seeing pop star Madonna, actress Tina Fey and "Desperate Housewives" star Eva Longoria-Parker in upcoming episodes.

"Perhaps foremost, 'The Marriage Ref' provides light entertainment at a time when silliness represents a balm to grim tidings elsewhere," said Daily Variety.

Other new shows being launched this week by NBC include family drama series "Parenthood" and "Who Do You Think You Are?" in which Sarah Jessica Parker, Spike Lee, Lisa Kudrow and other celebrities trace their family roots.

Monday also sees the return of Leno to "The Tonight Show" following the controversial exit in January of Conan O'Brien after just seven months in the job.

(Editing by Bob Tourtellotte and Eric Walsh)