Thanks in part to increased interest around Serena Williams’s retirement, this year’s U.S. Open tennis championship was a grand slam for TV advertisers, as data from iSpot reveals.

From Aug. 29-Sept. 11, the U.S. Open delivered 1.94 billion TV ad impressions, which was up 88.4% from 1.03 billion last year. The 2022 U.S. Open was the No. 4 program by TV ad impressions delivered in the timeframe, at 1.97% — versus 1.01% in 2021.

The growth in viewership (and impressions as a result) sustained above last year nearly every single day, and can be attributed to a variety of factors: Most notably, the surge in interest around Williams, whose matches drove the most TV ad impressions per airing of the entire tournament.

On its most viewed day (Sept. 5), the U.S. Open served up 248 million TV ad impressions, which is equal to 25% of the total delivered during last year’s tournament.

Among the top advertisers to benefit from the year-over-year jump were IBM (6.52% of TV ad impressions during the event), American Express (6.45%), Uber Eats (3.85%), JPMorgan Chase Banking (3.56%) and Heineken 0.0 (3.51%). IBM, in particular, had the two most-seen ad airings of this year’s U.S. Open, which both appeared during Williams’s final match in the third round.