The Dallas Mavericks struggled in Game 1 of the NBA Finals against the Boston Celtics, and the viewership numbers were similarly disappointing.

The Celtics dominated the Dallas Mavericks in the opening game of the NBA Finals with a resounding 107-89 victory, fueled by the return of center Kristaps Porziņģis. The Latvian star hadn't played in 38 days due to a calf strain.

Thursday’s Game 1 of the NBA Finals between the Mavericks and Celtics averaged a 5.7 rating and 10.99 million viewers on ABC (11.04 million including 43,000 on ESPN Deportes). This makes it the least-watched Game 1 since 2007, excluding the two COVID-era series in 2020 (Heat-Lakers: 4.1, 7.69M) and 2021 (Bucks-Suns: 4.5, 8.70M).

New NBA Finals viewership low since 2007

Outside of the COVID seasons of 2020 and 2021, the last time an NBA Finals Game 1 had viewership this low was in 2007. Before the pandemic, the NBA Finals had six consecutive seasons where the opening game drew fewer than 14 million viewers.

Ratings and viewership dropped by 5% compared to last year’s Heat-Nuggets Game 1, which garnered a 6.0 rating and 11.58 million viewers on ABC and ESPN2. When compared to the 2022 Finals featuring the Celtics against the Warriors, ratings fell by 11% and viewership decreased by 8% from the previous 6.4 rating and 11.90 million viewers.

Not everything is bad for the NBA

Despite the lower overall viewership, The Mavericks-Celtics matchup achieved a significant milestone by delivering the largest Game 1 audience share ever on ABC at 20.3 percent, which was four times higher than the nearest competition on television, according to Nielsen data.

Moreover, the game also saw a record audience share in the coveted 18-34 demographic at 49.6 percent, marking the highest ever for an NBA Finals Game 1 on ABC.

The Celtics' 18-point win matched the Los Angeles Lakers' 2020 victory over Miami in the “bubble” as the most one-sided Finals opener since 2017. Ratings and viewership peaked at 6.2 and 12.11 million, respectively, during the 9:15 quarter-hour, but significantly declined to 4.8 and 9.01 million by the 10:45 quarter-hour.

Game 1 garnered a 3.5 rating in adults 18-49, a 2.9 in 18-34, and a 4.0 in 25-54, marking a decline of 6%, 9%, and 6% respectively compared to last year's figures of 3.7, 3.2, and 4.2.

This extends a trend of the NBA Finals starting below 14 million viewers for six consecutive years, the longest such streak since a seven-year period from 2003-2009.

Not counting the pandemic era, the most recent NBA Finals appearance for the Celtics was in 2010, where their 102-89 loss to the Lakers drew an average of 14.1 million viewers. The series was fiercely contested, going to a full seven games, and the deciding broadcast pulled in a robust 28.2 million viewers.

Good sign for the Dallas Mavericks?

The Mavericks appeared quite disorganized on Thursday evening, but those overseeing ABC's ad sales aren't showing any signs of alarm. After all, Dallas lost the first game of their six-game series against the Los Angeles Clippers and were then convincingly defeated by the Oklahoma City Thunder 117-95 in the second-round opener. Interestingly, in both instances, the Mavericks rebounded to win Game 2 and eventually clinched the series.

Top advertisers in Game 1 included YouTube TV, Universal Pictures, State Farm, Samsung, Kia, AT&T, and Warner Bros. Out of the 95 marketers investing in the NBA Finals, 63 are returning sponsors, and 32 are new to the championship series.

The upcoming NBA Finals Game 2 is scheduled for this Sunday, June 9, at 8 p.m. ET on ABC from TD Garden in Boston, Massachusetts.