The big shows last night on TV were football and Bill Clinton. The NFL regular season kicked off on NBC (8.7/23) as the Dallas Cowboys beat the defending Super Bowl champs the New York Giants. However, it wasn’t all touchdowns — this year’s 8:30-11 PM ET opener was down 15% from the 10.2/27 fast nationals of last season’s September 8 opener. Nonetheless, the Cowboys-Giants game dominated the night, pulling in 21.81 million viewers and leading NBC to the nightly win in total viewers and adults 18-49. The network’s 8:30 PM NBC Sports NFL Kickoff (5.5/17) was also down from last year, falling 14% from the 6.4/21 of last September 8.

Because of football, NBC did not cover former President Clinton’s much-anticipated speech at the Democratic National Convention, but ABC and CBS did. Both networks earned a 0.9.2 in that 10-11 PM ET slot, virtually flat with the comparative night at the 2008 convention. Based on fast affiliates estimates, the numbers for the networks’ live coverage of the DNC and NBC’s NFL game are likely to change later today.

CBS also had Big Brother (2.1/6) last night. The reality show was down 9% from last week. On Fox, it was a two-hour So You Think You Can Dance (1.4/4), down 7% as it cut to four finalists heading toward the season finale September 18. Otherwise, ABC ran repeats with The Middle (1.1/4), Suburgatory (0.9/2), Modern Family (1.3/3) and another Suburgatory (1.0/3). CBS had an encore of Criminal Minds (1.2/3) at 9 PM.