Among total viewers, the game was seen by 16.9 million, up 31 percent.
The figures reverse a World Series Game 1 downward trend in recent years, despite the match being a blowout, with the Sox winning 13 to 1.
Although the rating is preliminary and therefore subject to shift in the nationals, Fox expects the figure to hold up.
Like any major sporting event, the game throws its competitors numbers off balance, making week-to-week comparisons suspect.
That said, ABC came in second place with "Pushing Daisies," down 19 percent from last week to a 3.0, which is a rather steep drop even with the game, particularly since "Private Practice" was up a couple notches to a 4.5. At 10 p.m., "Dirty Sexy Money" also was up slightly to a 3.2.
CBS is up a peg for the second consecutive week, with "Kid Nation" earning a 2.5. "Criminal Minds" was down a tick to a 3.9 and "CSI: NY" was down 7 percent to a 3.8.
Coming in fourth, NBC premiered "Phenomenon" at 8 p.m. to a 2.9, besting the time-period debut of "Deal or No Deal" in the slot in September.
The live show featured "mentalists" performing their acts for judges Uri Geller and Criss Angel with the help of celebrities. The acts included one performer playing Russian roulette with a series of nailguns and another making Carmen Electra claim she felt his touch from several feet away.
Following "Phenomenon," NBC had "Bionic Woman," which was down a notch to a 3.3, and then "Life," dropping 11 percent to a 2.5.
On The CW, "America's Next Top Model" was down slightly to a 2.3, while "Gossip Girl" was steady with a 1.2. The story is the same in The CW's target 18 to 34 demo.