ESPN has shown most of the women’s tournament since 1996, when it took over the rights from CBS. The only games to draw larger audiences than the Iowa-South Carolina matchup were two tournament finals in the early 2000s, featuring Diana Taurasi and a juggernaut Connecticut team that won three consecutive championships.

On Friday night, Clark showcased her shooting and other offensive skills for Iowa while matched up against a previously undefeated South Carolina team that had been the heavy favorite to win a second consecutive championship. The game more than delivered on those high expectations, with Clark scoring 41 points — her second consecutive 40-point game — and Iowa holding off several late pushes by the Gamecocks, who showcased their depth even in defeat.

The strong viewership for Iowa-South Carolina, and the 3.4 million average viewers of the other tight semifinal game, between Louisiana State and Virginia Tech, contributes to what has already been a highly watched tournament. Before Friday night’s games, viewership was already up 42 percent compared to last year’s tournament.

Sunday’s final, featuring Iowa and L.S.U., will not be in its traditional prime-time slot and will instead start at 3 p.m. Eastern. But it will be on ABC, the first time in decades the final has been shown on a broadcast channel, which is available in more homes than cable channels like ESPN and ESPN2.

While ESPN is celebrating the high interest in the tournament, that could also result in the company, or a different broadcaster, having to spend more money in the future. ESPN’s rights to show the tournament, and 28 other N.C.A.A. title events, expire next year. A report commissioned by the N.C.A.A. found that the women’s tournament could be worth at least $85 million in 2025; the N.C.A.A. valued the tournament at only $6 million in ESPN’s current agreement.

There have been pushes within college sports to break out the women’s tournament to maximize its value and sell the rights separately, like the N.C.A.A.’s deal with CBS and Turner Sports for the men’s tournament.

The viewership for the semifinal games, measured by Nielsen, is not yet finalized. ESPN released early data based on what is called fast nationals, a smaller sampling of viewership that is quickly processed. The final viewership data will not be known until early next week. While sometimes final ratings differ significantly from fast nationals, usually they do not.

And while it is clear that Friday night’s matchups were widely viewed, and that across the board more people are watching women’s college basketball, women’s professional basketball and women’s soccer, there is one large caveat that makes it difficult to fully compare viewership to years past.

In 2020, Nielsen began incorporating what it calls out-of-home viewing into its ratings data. This measurement, which TV networks pushed to include in ratings for years, takes into account people watching television at bars, airports, gyms and other locations outside of their own homes. In particular, the change boosts viewership data for sports more often than for scripted programming, as sports are more likely to be shown on television in those public settings.

While it depends on the specific sport, out-of-home viewing tends to boost ratings anywhere from 5 to 10 percent. Or, to put it a different way, if Nielsen measured out-of-home viewing back in 2002 when Connecticut defeated Oklahoma, it might have measured 6 million people watching the game instead of 5.7 million.

Still, to understand the growth in popularity of women’s college basketball, one only needs to look at viewership for the men’s tournament. Viewership for all windows of the men’s Regional semifinals and Regional finals last weekend were down compared with last year — some of them by more than 20 percent.