The four games on Fox averaged a 7.6 rating and 12 share, Nielsen Media Research said Monday. The previous low was an 8.4 for the 2008 Phillies-Rays and 2010 Giants-Rangers series, which each went five games.
Last year's Cardinals-Rangers World Series went the full seven games and built momentum to average a 10.0/16.
San Francisco's 2-0 win in Game 3 on Saturday night earned a 6.1/11, down from a 6.6/12 for St. Louis' 16-7 win over Texas in the third game last year and matching the lowest for any World Series game. Philadelphia's 5-4 win in Game 3 in 2008 also had a 6.1 rating on a night a rain delay pushed the start after 10 p.m. on the East Coast and the game didn't end until 1:47 a.m.
The Giants' 4-3, 10-inning victory in the finale Sunday night drew an 8.9/14, up slightly from the 9.2/14 for the Rangers' 4-0 win over the Cardinals in 2011.
Ratings represent the percentage of all homes with TVs tuned into a program. Shares represent the percentage watching among all homes with TVs in use at the time.
Fox said it projects to win Saturday and Sunday nights among viewers 18 to 49.
"The World Series has been a top-10 prime-time hit for over 40 years and even with a four-game sweep this series was no exception," said Michael Mulvihill, Fox Sports Media Group's senior vice-president of programming and research. "This World Series gave us exactly what we expected: a top-10 show among all viewers and a top five show among hard-to-reach younger men. It's important for us to remain focused on the Series relative to today's competitive environment rather than bygone years."
Fox televised the World Series in 1996, 1998 and has had exclusive rights since 2000. It has an eight-year deal with Major League Baseball through 2021 that includes Series rights and costs an average of about $500 million annually.
San Francisco had the highest rating for Game 4 at 38.7/64. Detroit was at 37.9/53.
Major League Baseball said there were 1,202,706 comments on social media for the Series finale, surpassing Game 6 last year for MLB's high. That included 171,024 comments within five minutes after the final out, topping the 97,000 for David Freese's winning home run in the sixth game last year, according to data from Bluefin Labs. The 10,671,781 social media comments for the post-season marked a 131 per cent increase from last year.