Trumaine Johnson had a terrific performance against the Eagles last week, locking down Alshon Jeffery before leaving the game with a stinger. It was one of his best showings of the season, but one controversial play overshadowed his strong outing.

Late in the third quarter, Johnson knocked away a pass intended for Alshon Jeffery on a crucial third down. It seemingly forced the Eagles to settle for a 50-yard field goal attempt, but a late flag after the play changed that.

Unsportsmanlike conduct, 15 yards, first down.

Rather than attempting a long field goal, the Eagles scored a touchdown eight plays later and took a 31-28 lead. That proved to be the difference in the game, and Wade Phillips knows it.

“We can’t have penalties after the play. I think that’s the first one we’ve had this season,” Phillips said Thursday. “It cost us at least four points and maybe seven, which might’ve been the difference in the ballgame.”

Nickell Robey-Coleman came out this week and said Johnson and Jeffery were just “talking football” and it was nothing beyond that. Johnson then posted on Snapchat that he and Jeffery are friends and it was just competition, going back and forth.

Trumaine Johnson was flagged 15 yards for unsportsmanlike conduct. A teammate says he was just ‘talking football’ https://t.co/rPWrmsiRla pic.twitter.com/CRE66XdhUt — Cameron DaSilva (@camdasilva) December 11, 2017

The official didn’t see it that way, which is all that matters.

“It was a selfish act, especially on that crucial drive,” Johnson said, via the L.A. Times. “What I take from it: Celebrate my teammates. It’s not just all about me. If I could take it back, I’d take it back.”

No one will lament Johnson for costing the Rams the game because they had plenty of opportunities to win. But Phillips doesn’t want his players to leave it up to the officials when it comes to unsportsmanlike conduct flags.

“I don’t think Trumaine was doing anything but talking to the guy, but you never know officials what they’re going to,” Phillips said. “He said they’re good friends which they probably are. But you just can’t do that during the game. You just got to celebrate on your own and don’t worry about talking to the other guy. We learned a tough lesson there, because like I said it could’ve cost us the ballgame and our players know that now.”

It’s a lesson learned, but that doesn’t change the outcome of Sunday’s game. All the Rams can do now is bounce back against a depleted Seahawks team.