DETROIT -- Jim Schwartz held the challenge flag in his hand, certain Houston's long touchdown wouldn't count. Running back Justin Forsett was clearly down around his own 25-yard line, and that's where the ball would be spotted once the play was reviewed.
Then Schwartz threw his red flag onto the field -- and in doing so, he ensured that the Texans' dubious scoring play would count.
"I know that we can't challenge a turnover or a scoring play and I overreacted," the Detroit coach said. "That's all my fault. I overreacted in that situation and I cost us a touchdown."
Schwartz's mistake was only the beginning. Detroit let a 10-point third-quarter lead slip away and lost 34-31 in overtime to the Texans on Thursday.
The Lions led 24-14 when Forsett scored on an 81-yard run, taking advantage of a blown call that couldn't be reviewed because of Schwartz's ill-advised challenge. Replays clearly showed Forsett's knee touching the ground around his own 25 -- Detroit players even slowed up, assuming the play was over.
Forsett got up and ran all the way to the end zone.
"I know now that I was down, but I didn't think I was during the play. I didn't think my knee hit, and there was no whistle, so I kept going," Forsett said. "I wasn't giving the touchdown back."
Scoring plays are reviewed automatically -- but if a coach throws a challenge flag like Schwartz did, the review is negated and an unsportsmanlike conduct penalty is assessed. So the touchdown stood despite obvious evidence it should never have happened.
"There should be no blame on Schwartz or the coaches," Detroit defensive lineman Kyle Vanden Bosch said. "I mean, there's enough plays left out there, enough plays that we could have made. There were 70-plus minutes."
Atlanta coach Mike Smith made a similar mistake a few days earlier against Arizona, throwing his challenge flag on a fumble that would've been subject to review anyway. Under the rules, he was assessed the unsportsmanlike conduct penalty and the play was not reviewed, costing the Falcons a chance to get the ball back.
Detroit (4-7) still led 24-21 after Forsett's touchdown, and the Lions took a 31-24 advantage on Joique Bell's 23-yard TD run with 13:31 left in the fourth.
Houston rallied, tying it at 31 on Arian Foster's 1-yard run with 1:55 to play. That touchdown capped a 15-play, 97-yard drive that included a conversion on fourth-and-7.
Texans kicker Shayne Graham missed from 51 yards in overtime, but Detroit's Jason Hanson hit the right upright from 47. Graham finally connected from 32 to win it.
Detroit extended its losing streak in its annual Thanksgiving showcase to nine. Vanden Bosch had a chance to change the outcome in overtime, but he was unable to hold onto an errant pass by Houston quarterback Matt Schaub that bounced off the defensive lineman's hands deep in Houston territory.
"It's going to be really tough to forget that one," Vanden Bosch said.
Hanson's miss came on third down after the Lions had lost 3 yards on a second-down run. The Lions sent the veteran kicker onto the field instead of trying to move the ball a bit closer.
"We didn't want to give up a negative play, and they'd been trying really hard to strip the ball, so we didn't want to risk a turnover," Schwartz said.
The Lions were hoping a three-game homestand could help revive their playoff hopes, but they lost against Green Bay last weekend and couldn't hold on against the Texans.
AFC South-leading Houston (10-1) has won five straight -- two in a row in OT -- and if a handful of teams lose, the Texans could be in the playoffs by the end of this weekend.
If the Lions didn'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. Suh didn't stick around long enough to talk to reporters after the game.
Last year on Thanksgiving, Suh was ejected for stomping on the right arm of Green Bay offensive lineman Evan Dietrich-Smith and was suspended for two games. He has been fined in previous seasons for roughing up quarterbacks: Cincinnati's Andy Dalton, Chicago's Jay Cutler and Cleveland's Jake Delhomme.
Schaub stayed in the game, and was 29 of 48 for 315 yards with a 9-yard TD to Owen Daniels that tied it at 14 late in the first half. He also threw an interception.
Houston's Andre Johnson had nine receptions for 188 yards.
Detroit's Matthew Stafford was 31 of 61 for 441 yards with two TDs -- tiebreaking scores to Calvin Johnson and Mike Thomas in the second quarter. It wasn't enough.
"We got what we deserved," Stafford said. "We didn't capitalize on our chances."
NOTES: Lions OT Jeff Backus (right hamstring) was inactive, ending his 186-game starting streak. ... Houston LB Brooks Reed (left groin) and OT Derek Newton (knee) were injured during the game.