Updated

Houston's Justin Forsett scored on an 81-yard touchdown run in the third quarter Thursday against the Detroit Lions, even though replays clearly showed his knee touching the ground near midfield.

It appeared Detroit coach Jim Schwartz helped the touchdown stand by throwing his challenge flag.

The TD counted and Detroit was called for unsportsmanlike conduct. A Lions spokesman said a coach is not allowed to challenge a scoring play, which is automatically reviewed — and if the coach does throw a challenge flag, the automatic review is negated.

Detroit coach Jim Schwartz was seen tapping his chest on the sideline, saying "it's on me" while talking to coaches and players.

The irate crowd at Detroit's Ford Field kept booing the call for several minutes, even as the game continued.