A pair of high-wattage games in the late afternoon window led the NFL to a huge audience on Sunday.

Deploying its first “double-doubleheader” of the season in which both CBS and Fox aired nationally televised games in the 4:25 p.m. ET window, the NFL drew nearly 40 million viewers on Sunday afternoon.

The CBS broadcast of the Buffalo Bills’ win over the Detroit Lions averaged 23.3 million viewers per Jon Lewis of Sports Media Watch. Simultaneously, the Philadelphia Eagles’ win over the Pittsburgh Steelers drew an average audience of 16.4 million viewers on Fox. Combined, 39.6 million viewers tuned in for Sunday’s late afternoon window.

It’s the first time the NFL has employed a double-doubleheader during the middle of the season, making comparisons difficult. Since expanding to a 17-game schedule, the NFL has scheduled competing doubleheaders on CBS and Fox during the first and last weeks of the season. That changed this year when the league allowed Fox to air its game unopposed in Week 1.

Per a report in Front Office Sports last week, the NFL moved its double-doubleheader back to later in the season so it had a clearer picture of who the best teams were. The strategy seems to have paid off. Fox’s traditional national window game during Week 15 last season averaged 26.3 million viewers.

CBS did start the day with a larger lead-in for its game. Per SMW, the network averaged 15.1 million viewers during its early afternoon window (primarily the Kansas City Chiefs-Cleveland Browns game), compared to just 9.8 million in the early window for Fox (mostly Dallas Cowboys-Carolina Panthers).

Outside of the afternoon windows, NBC’s Sunday Night Football between the Green Bay Packers and Seattle Seahawks averaged 17.9 million viewers between TV and streaming. ESPN’s Monday Night Football doubleheader featuring Chicago Bears-Minnesota Vikings and Atlanta Falcons-Las Vegas Raiders games averaged 17.8 million viewers during the overlap period, per ESPN PR.

[Sports Media Watch]