DETROIT — Jim Schwartz threw a challenge flag when he didn’t need to and the Houston Texans made him regret it.
Shayne Graham’s 32-yard field goal with 2:21 left in overtime lifted Houston to a 34-31 win over the Detroit Lions Thursday after their coach broke an NFL rule by attempting to challenge a scoring play.
‘‘Obviously that’s a big break in the game for us,’’ Houston coach Gary Kubiak said. ‘‘But I think you make your breaks when you work your tail off.’’
Detroit kicker Jason Hanson had a chance to get Schwartz off the hook, but his 47-yard field goal attempt on the fifth possession of the extra period hit the right upright.
Lions defensive end Kyle Vanden Bosch did, too, on the previous possession when he couldn’t intercept a pass Matt Schaub threw directly at him deep in Houston territory.
Detroit might've won in regulation if its coach didn’t make a costly mistake.
Schwartz threw a challenge flag when Houston’s Justin Forsett scored on an 81-yard touchdown run in the third quarter after two Lions tackled him.
‘‘Give him credit for continuing to play football,’’ Kubiak said. ‘‘We talk about that all the time. You don’t stop, you play.’’
Replays showed Forsett’s left knee and elbow hit the turf near midfield, and the automatic review that accompanies all scoring plays probably would have taken the TD off the board. But NFL rules say that throwing the challenge flag on a scoring play negates the review — and is an unsportsmanlike conduct penalty to boot.
‘‘It’s on me,’’ Schwartz could be seen saying to assistants and players on the sideline as he tapped his chest. ‘‘It’s on me.’’
Yes, it was.
Forsett even acknowledged he shouldn’t have been allowed to score.
‘‘I know now that I was down, but I didn’t think I was during the play,’’ he said. ‘‘I didn’t think my knee hit, and there was no whistle, so I kept going.
‘‘I wasn’t giving the touchdown back.’’
That score pulled Houston within 3 points.
‘‘I knew the rule — you can’t challenge on a turnover or a scoring play — but I was so mad that I overreacted,’’ said Schwartz. ‘‘I had the flag in my hand before he even scored because he was obviously down.’’
Kubiak had no sympathy.
‘‘A rule’s a rule,’’ Kubiak said. ‘‘I know one thing: You've got to keep your flag tucked in your pocket.’’
Arian Foster ran for 102 yards and two scores, including a 1-yard run with 1:55 left in the fourth quarter to cap a 15-play, 97-yard drive that tied the game at 31.
AFC South-leading Houston (10-1) took its first lead when Graham made up for missing a field goal earlier in OT after teammate Danieal Manning ripped the football away from Lions tight end Brandon Pettigrew at the Texans 32 on the first drive of the extra period.
The Texans have won five straight — two in a row in OT — and if a handful of teams lose they could be in the playoffs by the time they get back on to practice after a long weekend.
‘‘Ten quarters in five days, it’s draining physically and mentally,’’ Texans defensive end J.J. Watt said. ‘‘But our team persevered.’’
And, the Lions wilted and blew a fourth-quarter lead during a second straight setback.
Detroit (4-7) has lost three straight to make it extremely difficult to reach its goal of earning a spot in consecutive postseasons for the first time since the mid-1990s.
And as if the Lions don’t have enough problems, defensive tackle Ndamukong Suh could be in trouble with the league again after his left cleat connected with Schaub’s groin area in the first quarter.
‘‘I really don’t have anything to say about that play or that person,’’ Schaub said.
Suh was on his chest, taken down by an offensive lineman, when he extended his left foot below Schaub’s belt.
It wasn’t clear on replays whether the kick was intentional, but Suh might struggle to get the benefit of the doubt and perhaps that’s why he didn’t stick around long enough to talk to reporters after the game.