The New York Yankees-Boston Red Sox rivalry is as appealing today as it has been for generations. Fans will attest to that, and so will the viewership numbers. As the Red Sox completed their four-game series sweep against the Yankees on June 28, Sunday Night Baseball achieved one milestone and gave tough competition to the NBA.

The game was already underway, and at the bottom of the fourth inning when NBC joined the broadcast, it recorded an average of 4.0 million viewers on NBC and Peacock, per NBC Sports‘ press release. It became the most-watched game since the Yankees-Red Sox game on August 7, 2011, which aired on ESPN and recorded 4.72 million viewers. The 10-inning game on a Sunday night saw the Red Sox win 5-4.

Back in 1995, when NBC Sports hosted its first New York Yankees–Boston Red Sox game, it also ended in a one-run Red Sox victory, 3-2 in 10 innings. The broadcast showcased as much star power as possible, featuring Hall of Famers Derek Jeter, David Ortiz, and Mariano Rivera.

This is also the first season NBC has aired Sunday Night Baseball after ESPN held the broadcast rights from 1990 through last season.

Sunday’s game also became the most-viewed regular-season game since 2021, when the Yankees and the White Sox faced off at MLB’s Field of Dreams.

The recent numbers have brought the NBA into the conversation, giving it head-to-head competition. Only four Sunday Night Basketball games on NBC have surpassed the Yankees’ viewership total: Rockets–Thunder, Celtics–Lakers, Warriors–Lakers, and Lakers–Knicks.

Prior to the Yankees-Red Sox game, the Opening Day clash between the Arizona Diamondbacks and the Los Angeles Dodgers was the most-watched regular-season baseball game on NBC and Peacock. It recorded 3.16 million viewers. To top that, NBC has actually recorded five of the 10 most-watched MLB games so far this season, and three of the top five.

However, the NBC broadcast of the most-watched Sunday Night Baseball game in 15 years did not begin until the fourth inning.

The first three innings were streamed exclusively on Peacock and NBCSN. At the same time, NBC and Peacock were also broadcasting the PGA Tour’s Travelers Championship.

The tournament helped boost the baseball broadcast’s audience, as many viewers stayed on to watch Sunday Night Baseball after the championship concluded. The Travelers Championship peaked at 5.6 million viewers as tied leaders Viktor Hovland and Scottie Scheffler played the 18 hole, surpassing the Red Sox–Yankees broadcast. Overall, NBC Sports recorded the event’s most-watched final round since 2002, as it averaged 4.2 million viewers across NBC and Peacock.

According to Awful Announcing, Nielsen Media Research shifted to Big Data and Panel Methodology in September 2025. It helped boost streaming numbers. The final number of 4 million people who watched the game also included the streaming numbers from Peacock, which Adobe Analytics evaluated.

While the game itself delivered on the field, its biggest victory may have come off it. And with the new viewership milestone, the Yankees–Red Sox matchup has once again proved why it remains one of the most iconic rivalries in all of sports.