The biggest audience for a World Series game in two years – though below the previous Game 6 two years ago – watched the Boston Red Sox win Major League Baseball’s championship Wednesday on Fox.

Fox could celebrate the numbers even as it lamented Thursday’s lost potential Game 7, which likely would have gone several million higher.

According to preliminary nationals from Nielsen, Boston’s 6-1 victory over St. Louis in Game 6 drew 18.0 million viewers, compared with the 21.1 million that watched the last World Series Game 6, in 2011 between St. Louis and Texas. (The trend is for the final same-day nationals to inch approximately one million higher above the preliminary nationals.)

The following night in 2011, St. Louis won the World Series before an audience of 25.4 million. That game was played on a Friday, when TV viewing declines, meaning that Fox might have expected as much or a bit more for a Thursday Game 7 this year, albeit on Halloween.

The only other Game 6 in the past 10 seasons, in 2009, drew 22.3 million to see New York Yankees win the World Series over Philadelphia.

Among adults 18-49, this year’s Game 6 had a 5.4 rating and 15 share, compared with 4.4/11 for Sunday’s Game 4 and 3.8/10 for Sunday’s Game 5. The event gave Fox the most-watched Wednesday night in 18-49 since Jan. 30 and the best in total viewers since Sept. 5, 2012.

CBS finished second Wednesday in primetime, with original episodes of “Survivor” (2.3/7 in 18-49, 9.0 million overall), “Criminal Minds” (2.4/6, 10.6 million) and “CSI” (1.8/5, 9.6 million). The Eye won in all three hours among non-sports programming.

Settling into third place throughout the night was ABC, with “The Middle” (2.1/7, 8.0 million), “Back in the Game” (1.7/5, 6.2 million), “Modern Family” (2.2/6, 7.4 million), “Super Fun Night” (1.8/5, 5.4 million) and “Nashville” (1.4/4, 5.2 million). Of that brew, only “Modern Family” was a repeat.

NBC was fourth in all timeslots with a new episode of “Revolution” (1.4/4, 4.9 million) and a two-hour repeat of “Law & Order: SVU” (1.0/3, 4.2 million). The CW then came in with a new episode of “Arrow” (0.7/2, 2.3 million), followed by “The Tomorrow People” (0.6/1, 1.7 million).

“Revolution” matched its 18-49 rating of the previous two weeks.

Preliminary 18-49 averages for the night: Fox 5.4/15, CBS 2.2/6, ABC 1.8/5, NBC 1.2/3, Univision 1.1/3, CW 0.6/2.

In total viewers: Fox 18.0 million, CBS 9.7 million, ABC 6.3 million, NBC 4.4 million, Univision 3.1 million, CW 2.0 million.