Not even the mighty Tom Brady on Sunday could reverse the NFL’s ratings slide.

The never-bet-against New England Patriots quarterback, who engineered yet another come-from-behind win in the AFC Championship game, helped the NFL pull a 27.3 Nielsen overnight rating on CBS — down slightly from last year.

On the upside, the massive audience — a 50 percent share of TVs in use, according to the network — was the highest-rated TV program since last year’s Super Bowl.

Those competing facts — that NFL ratings continue to erode but that the league still outdraws, by far, the Academy Awards (an 18.4 rating), Game 7 of the World Series (15.8), the college football championship game (14.2) and the NBA Finals (13.5) — make for a puzzling quandary for football boss Roger Goodell.

The NFL’s NFC championship game in the late slot on Sunday, which saw the Philadelphia Eagles beat the Minnesota Vikings 38-7, drew a 24.4 rating on Fox — down 11 percent from last season.

It was the lowest-rated NFC title game since 2009, and the lowest-rated late-window conference championship since 2015.