The 49ers lost too many quarterbacks. The Bengals, in the game’s most critical moment, lost their wits. New York football fans, by the end of a long Sunday, likely felt they had lost a day that began with such promise.

The NFL had it all set up, with arguably the four best teams it could offer pitted against each other for the conference championships. What might have been an electric day of football instead was filled with a blowout, a good game that deserved a better ending and, locally, a bizarre building controversy.

Let’s start with the poor 49ers. A matchup of defensive powerhouses and brilliant offensive minds was doomed nearly from the start. Perhaps the play that the game will be remembered for — Devonta Smith’s leaping, one-handed grab down the left sideline on a fourth-and-3 — should not have counted: Replays later showed the ball was bobbled and hit the ground. The best angle of the catch was not seen soon enough, which set up the Eagles’ first touchdown, creating a lead the 49ers would never approach because of their quarterbacking disaster.

Brock Purdy — the third quarterback they have trusted this season — suffered an elbow injury in the first quarter that essentially prevented him from making a pass the rest of the game. Head coach Kyle Shanahan turned to fourth-string journeyman Josh Johnson, who quickly sustained a concussion that kept him out for the game. Without an arm that could throw the ball downfield, the 49ers had no hopes of escaping a hole and slogged to a 31-7 defeat in a contest that was barely watchable.