According to Nielsen overnight data, the GOP debate--which aired between 8 and 10 p.m. ET--drew 3.6 million total viewers, including 1.1 million in the 25-to-54-year-old demographic coveted by advertisers.
Those numbers were enough to outpace ratings powerhouse Fox News, which claimed 1.9 million total viewers and 370,000 25-to-54-year-olds during the two-hour span. MSNBC, with 643,000 total viewers and 161,000 in the 25-to-54 demo, was a distant third.
CNN also managed to increase the audience from its last GOP debate broadcast, on June 13. That one drew 3.2 million total viewers, and 918,000 24-to-54-year-olds.
CNN's ratings win came despite stiff competition from the TV sports world. The debate was up against the first "Monday Night Football" broadcast of the 2011-2012 NFL season on ESPN, and also overlapped with the four-hour-plus U.S. Open men's tennis championship on CBS. (Total viewers for "Monday Night Football" have yet to be released. But according to TVByTheNumbers.com, the "MNF" broadcast of the New England Patriots-Miami Dolphins game--from 7 p.m. to 10:30 p.m. ET--delivered a total rating of 14.568, compared to a 3.613 for CNN's debate.)
Still, CNN was unable to match last week's NBC/Politico-produced debate. The event drew 5.4 total viewers for MSNBC on Thursday, and 1.7 million 25-to-54-year-olds.
Fox News' GOP debate on Aug. 11 drew more than 5 million total viewers, and 1.4 million in the 25-to-54 demo, per Nielsen.