MLB's League Championship Series its most viewed since 2017

Major League Baseball's postseason goes into its dream World Series matchup with its most-watched League Championship Series in seven years.

According to Nielsen, the two series averaged 5.35 million viewers on Fox, FS1 and TBS, its highest numbers since 2017.

According to MLB, Game 1 of the NLCS on Oct. 13 between the New York Mets and Los Angeles Dodgers averaged 20.6 million viewers combined in the United States and Japan.

The estimated 12.1 million average in Japan made it the second most-watched MLB postseason game in the nation's history. The most-viewed was on Oct. 11 when an estimated 12.9 million tuned in for the Dodgers' 2-0 victory over the San Diego Padres in the decisive fifth game of the National League Division Series.

Fox and FS1 averaged 5.62 million for the NLCS, which the Dodgers won in six games. That was the network's most-viewed championship series since 2019.

The ALCS between the New York Yankees and Cleveland Guardians on TBS averaged 4.9 million. Game 5, which saw the Yankees advance to its first World Series since 2009 with a 5-2 victory in 10 innings, averaged 5.6 million, a 33% increase over Game 5 of last year's ALCS between the Houston Astros and Texas Rangers.

The postseason average going into Friday's first World Series game between the Yankees and Dodgers is 3.96 million, which is a 5% increase over last year.

The first Fall Classic in 43 years between the Dodgers and Yankees should also be a boost after the least-watched World Series last year. The five-game series between the Rangers and Arizona Diamondbacks averaged 9.11 million. Game 3 set the record for the least-watched World Series game on record at 8.13 million.

The 2018 series between the Boston Red Sox and Los Angeles Dodgers averaged 14.1 million. Fox and MLB, though, would be thrilled if the numbers could somehow reach the 22.9 million average from 2016, when the Chicago Cubs beat Cleveland in seven games for their first championship since 1908.

"I think we're expecting at least a five-year high. And I think realistically, maybe we can get to an eight-year high. It would be a nice surprise if we did that," said Mike Mulvihill, Fox's president of insights and analytics. "When you think about Fox's history with baseball, at one time we thought it would be amazing if Boston ever broke through and won the World Series. That happened. And you think, well, what if the Cubs someday won the World Series? Then that happened. This is sort of the last thing that we've never had that we now have a chance to cover."