Reality TV hits Joe Millionaire and American Idol have helped Fox Television win the latest round of the US ratings battle - the sweeps.
Evan Marriot was the star of Joe Millionaire
It won the crucial fight for young adult viewers - the group most coveted by advertisers.
The network came from last place to beat NBC, which had topped the TV ratings in the past 12 rounds.
CBS, which airs Survivor and CSI, clocked up the biggest total number of viewers, with an average of 13.8 million.
This compared with 12.45 million for NBC, 12.1 million at Fox and 10.45 million for ABC.
Following the success of Joe Millionaire, Fox said it is creating a sequel and has devised a way of keeping the spirit of the show, where a construction worker posed as a millionaire.
The sweeps are conducted three times a year - in February, May and November - to collect viewing data in order to set advertising rates.
The sweeps period is a hard-fought campaign when networks roll out their best programmes in prime-time slots.
Kelly Clarkson won the first American Idol series
NBC was number two in pulling in the 18-49 demographic, according to Nielsen Media Research.
Viacom, the company behind to CBS, was third while ABC, which is owned by Disney, was fourth.
The Joe Millionaire final was the highest-rating show in the sweeps for 18-49 year olds since the finale of the first Survivor series on CBS in August 2000.
The second series of American Idol also helped Fox achieve its ratings leap.
The opening night of the talent show, with warring judges Simon Cowell and Paula Abdul, was watched by 26.5 million people.
It also benefited from the airing the 300th episode of the animated family sitcom The Simpsons.
And the furore surrounding Michael Jackson helped secure massive ratings for both ABC and Fox.
ABC ran the original documentary showing the star being interviewed by UK journalist Martin Bashir.
Fox then bought the rights to the extra footage that Jackson said showed how Bashir had betrayed him and converted it into its own two-hour documentary.