The Peacock Network's coverage recorded a colossal 18-49 demo rating of 10.5 while drawing an audience of 32.1m between 8pm and 11pm.
Both viewing figures and demo ratings were higher than the ninth night for the Beijing Olympics back in 2008.
Patriotic Michael Phelps documentary, America's Golden Champion, enthralled 20.5m (5.9) in the 7pm hour.
Despite the huge swing to NBC, CBS's Big Brother managed to improve its audience to a 2.1 rating, having sunk to 1.9 last week.
Extreme Makeover: Weight Loss Edition returned to ABC's schedules with just 2.5m (0.7), while Secret Millionaire managed 3.8m (0.8) at 8pm.